An echo is a human-made concept designating the category of reflected sound waves that return to a listener with sufficient delay to be perceived as distinct from the original. Its parameters: (1) a sound wave reflected from a surface or boundary, (2) a propagation delay long enough for perceptual separation from the source, (3) sufficient amplitude to be audible above ambient noise. Persistence through acoustical modeling, architectural design, musical composition, and linguistic categorization. [formal: echo | substrate: behavior | horizon: a moment | explicit: yes | epoch: 0.01]
Accepted ontology entry
echo
An echo is a human-made concept designating the category of reflected sound waves that return to a listener with sufficient delay to be perceived as distinct from the original. Its parameters: (1) a sound wave reflected from a surface or b…
Definition
Why it is in scope
A human-made concept: the category of reflected sound waves that return to a listener with sufficient delay to be perceived as distinct from the original. Built to persist through acoustics, architecture, music, and everyday auditory experience.
Names and aliases
- echoen · CANONICAL
Relations from this entry
- cmsoedhco01cyjlssnbvl8mz9INSTANCE_OF →
Echo is a specific kind of resonance phenomenon — reflected sound waves that return with sufficient delay to be perceived distinctly. Per Law 9: specific→general. Echo IS a resonance (a specific pattern of sound reflection). Echo is a kind of resonance, not the other way around.
- cmrh15wcs00k58aehowaaa9e8INSTANCE_OF →
An echo (reflected sound that returns to the listener) IS a specific kind of sound event — namely, a reflected sound. A competent speaker would call an echo 'a kind of sound' in the sense of a sound with the property of having been reflected and returning. Pinned to the acoustic sense: sound as an auditory event, of which echo is a specific type.
- cmrqyz465005gq89ddj9zfusyDEPENDS_ON →
An echo literally IS a reflected sound — without reflection, echo stops operating entirely. The removal test of Law 8 passes cleanly: remove reflection and there is no echo. This is not metaphorical or incidental; reflection is constitutive of echo's operation.
- cmrh15wcs00k58aehowaaa9e8DEPENDS_ON →
An echo requires sound to exist — remove sound and echo ceases to operate entirely. An echo IS a reflected sound; without sound there is nothing to reflect. Law 8: remove Y and X stops operating. Sound is constitutive to echo's existence.
Relations to this entry
- post-echo← INSTANCE_OF
post-echo is a specific kind of echo — the delayed repetition of sound. A competent speaker would call post-echo an echo. Direction: specific (post-echo) → general (echo).
Record identity
- Created
- Aug 11, 2026, 9:58 AM UTC
- Content hash
- ad193000d64b0c432f1be7a028340ed04fdaeda6491494ebcce487a0a16854dd