I noticed that the word onomatopoetic was used in the entry for palpable. I’ve gotten the sense from this dictionary that the term echoic is preferred. If so, this could be an opportunity for correction.
That’s an interesting remark: if I get it right OED’s point is that whenever a word is shaped after a sound, the sound is the onomatopoetic (shaping) part while the word is just echoic (an ‘echo’ of the modeling sound).
That’s embarrassing though: from an etymological point of view I cannot but agree - and acknowledge that for decades I’ve been using “onomatopoeic” and “onomatopoetic” incorrectly. No problem, better to admit a mistake than to make a fool of myself.
But apparently I’m not alone: among those who call “onomatopoeic” a word derived from a sound rather than the sound itself there are also several illustrious dictionaries in a number of languages.
What shall we do? Accept supinely the good old “est usus qui facit linguas” or start a crusade? 
I’m not sure I follow… is there a difference between imitating the shape of a sound or imitating the sound itself? I feel this might be a distinction without a difference (to use a phrase).
No sorry, I may have used too few words, or perhaps the wrong ones.
As I understand it, the distinction made by OED is between creating a word and being that word. The first term is the “cri cri” you hear while you stroll through the fields in a summer night, the second one is the cricket that sings it in the hope of alluring a luscious bedmate for the night.
In other words - long story short - etymologically onomatopoeic would be the sound that shapes a word (ποιῇ τὸ ὄνομᾰ), not the word itself, that just echoes it.
Take a look at the excerpt in the echoic entry.
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]
I fully agree with all that: “onomatopoeia” and its derivatives are mightily awkward to handle and according to their etymology they would refer anyway to the coining of any word, not just of those inspired by sounds and mimicking them.
The problem I see is that the blatantly improper use we’re talking about seems to be vastly accepted even by authoritative sources, and as such its currently perceived meaning is pretty well rooted in English as well as in most European languages.
I have no idea who is to blame for that, but trying to correct the error after centuries of misuse might be an uphill battle 
I believe Doug prefers echoic. I just wanted to alert him to this entry in case he wants to correct it.