1880, "suggested by the Editor" (OED editor Sir James A.H. Murray) for "gradual and unintentional loss of a short unaccented vowel at the beginning of a word" [OED], as squire from esquire, venture from adventure. With -ic + aphesis (1880), from Greek aphienai "to let go, to send forth," from assimilated form of apo "from" (see apo-) + hienai "to send, throw" (from PIE root *ye- "to throw, impel"). Compare apheresis.
Onomatopoeia, in addition to its awkwardness, has neither associative nor etymological application to words imitating sounds. It means word-making or word-coining and is strictly as applicable to Comte's altruisme as to cuckoo. Echoism suggests the echoing of a sound heard, and has the useful derivatives echoist, echoize, and echoic instead of onomatopoetic, which is not only unmanageable, but when applied to words like cuckoo, crack, erroneous; it is the voice of the cuckoo, the sharp sound of breaking, which are onomatopoetic or word-creating, not the echoic words which they create. [James A.H. Murray, Philological Society president's annual address, 1880]