somewhere along the lines of history, they added the 'reverb' knob to amps - and from there, people seemed to think any form of DECAY is REVERB.
it is not, although many use it as slang. but most do not appear to understand the true definition of REVERB and thus REVERBERANT SOUND-FIELD, and the volume requirements required to support such energy flows.
a reverberant sound-field is one where the energy flows are statistically equal and probable in every direction. one cannot resolve an indirect specular reflection's gain, time arrival (with respect to the direct signal), and vector (direction). the energy is "well-mixed".
and the bounded acoustical space's volume required to support such a reverberant sound-field at a given frequency is dictated by Dr. Manfred Schroeders work in this field - and also his FsubL equation.
without the existence of a statistically "random-incidence" "diffuse-field", you do not have "reverb".
people seem to imply any form of signal decay or acoustical decay of a bounded space as being "reverb". this is entirely incorrect. in small acoustical spaces that lack the volume to support a reverberant sound-field at a given frequency, we instead of focused specular reflections and modal issues - all local areas of variable pressure with respect to the ambient noise floor. what reverberation that DOES exist is above our hearing range and below the ambient noise floor. this is also why you do not have a critical-distance (Dc) of which the reverberant sound-field becomes louder in gain than the direct signal. this is also why RTxx (RT60) calculations and Sabine's equations are entirely irrelevant unless one is within a Large Acoustical Space.
and now with Plate Reverbs or any other "FX" knob that applies a form of decay to a signal
... the propagation of incorrect use (eg, hijacking) of the term REVERB continues.