mid-14c., "sound repeated by reflection," from Latin echo, from Greek ēkhō, personified in classical mythology as a mountain nymph who pined away for love of Narcissus until nothing was left of her but her voice, from or related to ēkhē "sound," ēkhein "to resound," from PIE *wagh-io-, extended form of root *(s)wagh- "to resound" (source also of Sanskrit vagnuh "sound," Latin vagire "to cry," Old English swogan "to resound"). Related: Echoes. Echo chamber is attested from 1937.
"meaningless repetition of words and phrases," 1876, from German (von Romberg, 1865), from Greek ēkhō (see echo (n.)) + lalia "talk, prattle, a speaking," from lalein "to speak, prattle," of echoic origin.
"oral instruction, catechism," 1753, from Latinized form of Greek katēkhesis "instruction by word of mouth," from katēkhein "to instruct orally," originally "to resound" (with sense evolution via "to sound (something) in someone's ear" to "to teach by word of mouth"). This is from kata "down" (in this case, "thoroughly;" see cata-) + ēkhein "to sound, ring," from ēkhē "sound" (see echo (n.)).
1880; see echo (n.) + -ic. A word from the OED.
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]
digraph used in Old French for the "tsh" sound. In some French dialects, including that of Paris (but not that of Picardy), Latin ca- became French "tsha." This was introduced to English after the Norman Conquest, in words borrowed from Old French such as chaste, charity, chief (adj.). Under French influence, -ch- also was inserted into Anglo-Saxon words that had the same sound (such as bleach, chest, church) which in Old English still was written with a simple -c-, and into those that had formerly been spelled with a -c- and pronounced "k" such as chin and much.
As French evolved, the "t" sound dropped out of -ch-, so in later loan-words from French -ch- has only the sound "sh-" (chauffeur, machine (n.), chivalry, etc.).
It turns up as well in words from classical languages (chaos, echo, etc.). Most uses of -ch- in Roman Latin were in words from Greek, which in Greek would be pronounced correctly as /k/ + /h/, as in modern blockhead, but most Romans would have said merely /k/, and this was the regular pronunciation in English. Before c. 1500 such words were regularly spelled with a -c- (Crist, cronicle, scoole), but Modern English has preserved or restored the etymological spelling in most of them (chemical, chorus, monarch).
Sometimes ch- is written to keep -c- hard before a front vowel, as still in modern Italian. In some languages (Welsh, Spanish, Czech) ch- can be treated as a separate letter and words in it are alphabetized after -c- (or, in Czech and Slovak, after -h-). The sound also is heard in words from more distant languages (as in cheetah, chintz), and the digraph also is used to represent the sound in Scottish loch.
late 14c., resownen, resounen, of a place, "re-echo, sound back, return an echo; reverberate with," from Anglo-French resuner, Old French resoner "reverberate" (12c., Modern French résonner), from Latin resonare "sound again, resound, echo" (source also of Spanish resonar, Italian risonare), from re- "back, again" (see re-) + sonare "to sound, make a noise" (from PIE root *swen- "to sound").
With unetymological -d- from mid-15c. (compare sound (n.1)). From 1520s of things. Related: Resounded; resounding.