I'm not sure if you might continue with further proposals along these lines, for other Life Lexicon entries. Based on a text search of the multi-page HTML version of the Lexicon, the term "signal" is used 274 times in the current version. I think the majority of those uses won't be objectionable to anybody.
However, about a hundred of the mentions of "signal" appear to me to be similar to the meaning used in the two definitions above. Below are some excerpts from various definitions. I don't claim that the excerpts are complete or representative, just that they all contain the word "signal". I skipped over quite a few other uses that seemed very unlikely to be controversial.
suggesting that anyone should work on editing all of these definitions. My preference would be to maybe add a sentence or two to the definition of "signal", to clarify that a commonly understood meaning of "signal" is "active object moving through circuitry" (or something along those lines). With that addition, I personally think all of these other definitions are fine as they are.
:asynchronous Indicates that precise relative timing is not needed for two or more input signals entering a circuit, or two or more sets of gliders participating in a glider synthesis. In some cases the signals or sets of gliders can arrive in any order at all - i.e., they have non-overlapping effects.
However, in some cases such as slow salvo constructions, there is a required order for some of the incoming signals. These signals can still be referred to as "asynchronous" because the number of ticks between them is infinitely adjustable: arbitrarily long delays can be added with no change to the final result. Compare synchronized.
:bait An object in a converter, usually a small still life, that is temporarily destroyed by an incoming signal, but in such a way that a usable output signal is produced. In general such a converter produces multiple output signals (or a signal splitter is added) and one branch of the output is routed to a factory mechanism that rebuilds the bait object so that the converter can be re-used.
:beehive stopper A Spartan logic circuit discovered by Tanner Jacobi on 12 May 2015. It converts an input glider signal into a beehive, in such a way that the beehive can cleanly absorb a single glider from a perpendicular glider stream. The circuit can't be re-used until the beehive "bit" is cleared by the passage of at least one perpendicular input.
:block factory Any factory circuit that produces a block in response to an input signal. For a useful high-clearance example see keeper.
:B track A track for B-heptominoes. A B-heptomino becomes a Herschel plus a block in twenty generations, so this term was nearly synonymous with Herschel track until the discovery of elementary conduits that convert a B directly to another B, or to some other non-Herschel signal output. See for example BRx46B.
:CatForce An optimized search program written by Michael Simkin in 2015, using brute-force enumeration of small Spartan objects in a limited area, instead of a depth-first tree search. One major purpose of CatForce is to find glider-constructible completions for signal conduits. An early CatForce discovery was the B60 conduit, which enabled a record-breaking new glider gun.
:century-to-glider converter Any signal circuit that accepts a century as input and produces a clean output glider. For example, in November 2017 Adam P. Goucher noticed that this previously known C-to-G converter can replace the century eater in Paul Callahan's bistable switch, producing an extra glider output.
:channel A lane or signal path used in construction circuitry. Until the invention of single-channel construction arms, signals in a channel would usually be synchronized with one or more coordinated signals on other paths, as in the Gemini, which used twelve channels to run three construction arms simultaneously, or the 10hd Demonoid which needed only two channels. See also Geminoid.
:circuit Any combination of conduits or converters that moves or processes an active signal. This includes components with multiple states such as period multipliers or switches, which can be used to build guns, logic gates, universal constructors, and other computation or construction circuitry.
:clearance In signal circuitry, the distance from an edge shooter output lane to the last unobstructed lane adjacent to the edge-shooter circuitry. For example, an Fx119 inserter has an unusually high 27hd clearance.
Also, oscillator and eater variants may be said to have better clearance if they allow gliders or other signals to pass closer to them than the standard variant allows. The following high-clearance eater1 variant by Karel Suhajda allows gliders to pass one lane closer on the southeast side, than is allowed by the standard fishhook shape.
:composite conduit A signal-processing conduit that can be subdivided into two or more elementary conduits.
:CP semi-Snark A period-multiplying colour-preserving signal conduit found by Tanner Jacobi in October 2017, producing one output glider for every two input gliders. It is made by replacing one of the eaters in a Snark with a catalyst found using Bellman. The catalyst causes the formation of a tub which requires a second glider to delete. However, this adds 5 ticks to the repeat time, so that it becomes 48. This is still 3 ticks faster than the CC semi-Snark.
:dirty Opposite of clean. A reaction which produces a large amount of complicated junk which is difficult to control or use is said to be dirty. Many basic puffer engines are dirty and need to be tamed by accompanying spaceships in order to produce clean output. Similarly, a dirty conduit is one that does not recover perfectly after the passage of a signal; one or more extra ash objects are left behind (or more rarely a catalyst is damaged) and additional signals must be used to clean up the circuit before it can be re-used.
:dormant An object that is either stable or oscillates without producing any output, until it is triggered by an appropriate signal, which then produces some desired action. For example, freeze-dried objects are dormant until the arrival of a particular glider.
:dr Short identifier for Dean Hickerson's 'drifter' search program, used at various times to find wires, eaters, higher-period billiard table configurations, and related signal-carrying and signal-processing mechanisms. See also drifter.
:eater1 ... This eater can be constructed using a simple two-glider collision, as shown in stamp collection. It is often modified in various ways, or welded to other objects, to allow tighter packing of circuits or to allow a signal stream to pass close by. See clearance for an eater1 variant that is 1hd shorter to the southeast than the standard fishhook form. An eater1 can also be used as a 90-degree one-time turner.
:edge shooter A gun or signal circuit that fires its gliders (or whatever) right at the edge of the pattern, so that it can be used to fire them closely parallel to others. This is useful for constructing complex guns. Compare glider pusher, which can in fact be used for making edge shooters.
:elbow Depending on context, this term may refer to a signal elbow or a construction elbow. See also elbow ladder.
:elementary conduit (quoted above)
:F171 An elementary conduit, the seventeenth Herschel conduit, discovered by Brice Due in August 2006 in a search using only eaters as catalysts...
The central eater in the group of three to the northwest can be removed to release an additional glider output signal on a transparent lane.
:first natural glider The glider produced at T=21 during the evolution of a Herschel. This is the most common signal output from a Herschel conduit.
:fuse A wick burning at one end... A fuse can burn arbitrarily slowly, as demonstrated by the example Blockic fuse below. A signal, alternating between glider and MWSS form, travels up and down between two rows of blocks in a series of one-time turner reactions.
:glider stopper A Spartan logic circuit discovered by Paul Callahan in 1996. It allows a glider signal to pass through the circuit, leaving behind a beehive that can cleanly absorb a single glider from a perpendicular glider stream.
:G-to-H A converter that takes a glider as an input signal and produces a Herschel output, which can then be used by other conduits. G-to-Hs are frequently used in stable logic circuitry. Early examples include Callahan G-to-H, Silver G-to-H, and p8 G-to-H for periodic circuits. A more compact recent example is the syringe.
:Herschel (stabilizes at time 128) The following pattern which occurs at generation 20 of the B-heptomino... Herschels are one of the most versatile types of signal in stable circuitry. R-pentominoes and B-heptominoes naturally evolve into Herschels, and converters have also been found that change pi-heptominoes and several other signal types into Herschels, and vice versa. See elementary conduit.
:Herschel circuit A series of Herschel conduits or other components, connected by placing them so that the output Herschels from early conduits become the input Herschels for later conduits. Often the initial component is a converter accepting some other signal type as input - usually a glider, in which case a syringe is most commonly used.
:Herschel loop A cyclic Herschel track. Although no loop of length less than 120 generations has been constructed it is possible to make oscillators of smaller periods by putting more than one Herschel in a higher-period track. In this way oscillators, and in most cases guns, of all periods from 54 onwards can now be constructed (although the p55 case is a bit strange, shooting itself with gliders in order to stabilize itself). A mechanism for a period-52 loop was found in April 2018, but it includes a stage where the signal is carried by a triplet of gliders so it may not be considered to be a pure Herschel loop. The missing period, 53, is a difficult case simply because 53 is prime and so no small sparkers or reflectors are available.
:Herschel stopper A method of cleanly suppressing a Herschel signal with an asynchronous boat-bit, discovered by Dean Hickerson. Here a ghost Herschel marks the location of the output signal, in cases where the boat-bit is not present. Other boat-bit locations that allow for clean suppression of a Herschel are also known.
:Herschel-to-glider The largest category of elementary conduit. Gliders are very common and self-supporting, so it's much easier to find these than any other type of output signal. A large collection of these H-to-G converters has been compiled, with many different output lanes and timings. These can be used to synchronize multiple signals to produce gun patterns or complex logic circuitry.
:highway robber Any mechanism that can retrieve a signal from a spaceship lane while allowing spaceships on nearby lanes to pass by unaffected. In practice the spaceship is generally a glider. The signal is removed from the lane, an output signal is generated elsewhere, and the highway robber returns to its original state.
:intermittent stream ... Intermittent streams can be used to transmit signals, where holes in the stream can also convey information. For example, the stream can be processed by an inverter having the same period
:Karel's p15 (p15) An oscillator discovered by Karel Suhajda on December 11, 2002. It consists of a period 15 rotor supported by the domino spark of a pentadecathlon. It provides accessible sparks that can be used to perturb reactions or thin signal streams.
:line-mending reaction (*this definition is out of date for other reasons*)
No simple mechanism is known to mend the gap which lies completely on one side of the line. However, it is technically possible to use construction arm technology to push objects through the gap to build and trigger a seed for the required synchronized signals on the other side.
:NW31 One of the most common stable edge shooters... The edge shooter output at the top has no additional clearance, so its use in creating convoys is limited: it can only add gliders on the outermost lanes of an existing glider salvo. Like the beehive version of SW-2, either output can be used to build logical OR gates, where multiple input signal paths are merged onto the same output path.
:overclocking A term used when a circuit can accept a signal at a specific period which it cannot accept at a higher period. A syringe is a simple example.
:over-unity reaction An important concept in gun and macro-spaceship construction. To be a good candidate for building one of these types of patterns with a new period or speed, a stationary reaction (for a gun) or a moving reaction (for a macro-spaceship) must be able to produce some number of output signals, strictly greater than the number of input signals required to maintain the reaction. The extra signal becomes a gun's output stream, or may be used in a variety of ways to construct the supporting track for a macro-spaceship. By implication, "over-unity" refers to the ratio of output signals to input signals.
If all signal outputs must be used up to sustain a stationary reaction, a high-period oscillator may still be possible. See emu for example.
:p8 G-to-H A small periodic variant of a stable two-glider-to-Herschel component found by Paul Callahan in November 1998 and used in the Callahan G-to-H, Silver reflector and Silver G-to-H. The minimum repeat time is 192 ticks, though some lower periods such as 96 are possible via overclocking. Here a ghost Herschel marks the output signal location...
:periodic For circuit mechanisms, "periodic" is the opposite of p1 or stable. Periodic circuits necessarily contain oscillators, and therefore they can generally only accept input signals that are synchronized to the combined period of those oscillators (but see universal regulator).
For signal streams, "periodic" means that signals will only be present in the stream at one out of every n ticks, where n is the period of the stream. In a periodic intermittent stream there may be gaps, so that signals do not always appear at every nth tick. However, if a signal does appear, its distance measured in ticks from previous and future signals will always be an exact multiple of n.
:period multiplier A term commonly used for a pulse divider, because dividing the number of signals in a regular stream by N necessarily multiplies the period by N. The term "period multiplier" can be somewhat misleading in this context, because most such circuits can accept input streams that are not strictly periodic.
:permanent switch A signal-carrying circuit that can be modified so that it cleanly absorbs any future signals instead of allowing them to pass. Optionally there may be a separate mechanism to restore the circuit to its original function.
:pseudo Opposite of true. A gun emitting a period n stream of spaceships (or rakes) is said to be a pseudo period n gun if its mechanism oscillates with a period greater than n. This period will necessarily be a multiple of n. If the base mechanism's period is instead a fraction of n, then a period multiplier must also be present which is considered to be part of the mechanism, and the gun as a whole is still a true period gun. For example, a filter may be used on a lower-period gun to produce a compound gun such as the true p48 gun.
Pseudo period n glider guns are known to exist for all periods greater than or equal to 14, with smaller periods being impossible. All known p14 guns are pseudo guns requiring several signal injections, so they are quite large. The following smaller example is a pseudo period 123 gun, interleaving the streams from two true period 246 guns ...
:quadri-Snark A period-multiplying colour-preserving signal conduit found by Tanner Jacobi in October 2017, producing one output glider for every four input gliders.
:racetrack A pattern in which a signal makes its way in a loop through an "obstacle course" of reactions in order to demonstrate various ways that the signal can be reflected, temporarily stored, and converted.
:reanimation A reaction performed by a convoy of spaceships (or other moving objects) which converts a common stationary object into a glider without harming the convoy. This provides one way for signals that have been frozen in place by some previous reaction to be released for use.
:recovery time The number of ticks that must elapse after a signal is sent through a conduit, before another signal can be safely sent on the same path. In general, a lower recovery time means a more useful conduit. For example, the Snark's very low recovery time allowed for the creation of oscillators with previously unknown periods, 43 and 53.
:repeat time The minimum number of generations that is possible between the arrival of one object and the arrival of the next. This term is used for things such as reflectors or conduits where the signal objects (gliders or Herschels, for example) will interact fatally with each other if they are too close together, or one will interact fatally with a disturbance caused by the other. For example, the repeat time of Dave Buckingham's 59-step B-heptomino to Herschel conduit (shown under conduit) is 58.
:self-supporting A type of pattern, specifically a macro-spaceship, that constructs signals or tracks or other scaffolding to assist its movement, but does not contain complete information about its own structure. Examples include the Caterpillar, Centipede, half-baked knightship, waterbear, and the Caterloopillars. Caterpillar has been used as a general term for self-supporting spaceships, but it is not very appropriate for the HBKs.
:semi-Snark Any small stable signal conduit that produces one output glider for every two input gliders, with a 90 degree reflection. These can act as period-doublers for any glider stream whose period is at least equal to their repeat time, and so adding one of these to a single glider gun often results in a pattern much smaller than the older technology of crossing the output of two guns.
:signal elbow A conduit with signal output 90 degrees from its input. This term is commonly used only for signal wires, particularly 2c/3 signals. A Snark could reasonably be called a "glider elbow", but glider reflector is the standard term. A signal elbow with a recovery time less than 20 ticks would enable a trivial proof that Conway's Life is omniperiodic.
:speed booster Any mechanism which allows a signal (indicated by the presence or absence of a spaceship) to move faster than the spaceship could travel through empty space.
:splitter A signal converter that accepts a single input signal and produces two or more output signals, usually of the same type as the input. An older term for this is fanout, or "fanout device".
:stable pseudo-Heisenburp A multi-stage converter constructed by Dave Greene in January 2007, using a complex recipe found by Noam Elkies to insert a signal into a 2c/3 wire. The wire's high transmission speed allows a signal from a highway robber to catch up to a salvo of gliders.
:staged recovery A type of signal-processing circuit where the initial reaction between catalysts an incoming signal results in an imperfect recovery. A catalyst is damaged, destroyed completely as in a bait reaction, or one or more objects are left behind that must be cleaned up before the circuit can be reused. In any of these three cases, output signals from the circuit must be used to complete the cleanup.
:stop and restart A type of signal circuit where an input signal is converted into a stationary object, which is then re-activated by a secondary input signal. This can be used either as a memory device storing one bit of information, or as a simple delay mechanism. In the following January 2016 example by Martin Grant, a ghost Herschel marks the output signal location, and a "ghost beehive" marks the location of the intermediate still life.
:switch A signal-carrying circuit that can send output signals to two or more different locations, depending on the state of the mechanism. These may be toggle circuits, where the state of the switch changes after each use, or permanent switches that retain the same state through many uses until a change is made with a separate signal.
:synchronized Indicates that precise relative timing is required for two or more input signals entering a circuit, or two or more sets of gliders participating in a glider synthesis. Compare asynchronous. See also salvo and slow glider construction.
:syringe A small stable converter found by Tanner Jacobi in March 2015, accepting a glider as input and producing an output Herschel As of June 2018 it is the smallest known converter of this type, so it is very often used to handle input gliders in complex signal circuitry, as described in Herschel circuit.
:track (quoted above)
:transparent In signal circuitry, a term used for a catalyst that is completely destroyed by the passing signal, then rebuilt. Often (though not always) the active reaction passes directly through the area occupied by the transparent catalyst, then rebuilds the catalyst behind itself, as in the transparent block reaction. See also transparent lane.
:tremi-Snark A colour-preserving period-multiplying signal conduit found by Tanner Jacobi on 7 September 2017, producing one output glider for every three input gliders.
:trigger A signal, usually a single glider, that collides with a seed constellation to produce a relatively rare still life or oscillator, or an output spaceship or other signal.
:one-time turner ... A one-time turner reaction can be used as part of a glider injection mechanism, or as a switching mechanism for a signal.
:twin bees shuttle (p46) Found by Bill Gosper in 1971, this was the basis of all known true p46 guns, and all known p46 oscillators except for glider signal loops using Snarks, until the discovery of Tanner's p46 in 2017.
:universal regulator A universal regulator can allow two complex circuits to interact safely, even if they have different base periods. For example, signals from a stable logic circuit could be processed by a period-30 mechanism, though the precise timing of those signals would change in most cases.
:wire A repeating stable structure, usually fairly dense, that a signal can travel along without making any permanent change. Known wires include the diagonal 2c/3 wire, and orthogonal lightspeed wire made from a chain of beehives. Diagonal lightspeed wires are known, but the required signals are fairly complex and have no known glider synthesis. (*this definition is out of date for other reasons*)