word-forming element meaning "like, like that of, thing like a ______," from Latinized form of Greek -oeidēs (three syllables), from eidos "form," related to idein "to see," eidenai "to know;" literally "to see" (from PIE *weid-es-, from root *weid- "to see"). The -o- is connective or a stem vowel from the previous element. Often implying an incomplete or imperfect resemblance to the thing indicated.
"to draw air into and expel it from the lungs; to inhale and exhale (a scent, etc.)," c. 1200, not in Old English, but it retains the original Old English vowel of its source word, breath. To breathe (one's) last "die" is from 1590s. To breathe down the back of (someone's) neck "be close behind" is by 1946. Related: Breathed; breathing.
The vowel substitution was originally made by the Masoretes as a direction to substitute Adhonai for "the ineffable name." European students of Hebrew took this literally, which yielded Latin JeHoVa (first attested in writings of Galatinus, confessor to Leo X, 1516). Jehovah's Witnesses "member of Watchtower Bible and Tract Society" first attested 1933; the organization founded c. 1879 by Charles Taze Russell (1852-1916); the name from Isaiah xliii.10.
Canaanite god frequently mentioned in Scripture, said to have been propitiated by sacrificing children (Leviticus xviii.21), from Latin Moloch, from Greek Molokh, from Hebrew molekh, from melekh "king," altered by the Jews with the vowel points from basheth "shame" to express their horror of the worship. Hence, figuratively, "any baleful influence to which everything is sacrificed" (1799).
mid-13c., "action of waiting," verbal noun from abiden "to abide" (see abide). It is formally identical with the old, strong past participle of abide (Old English abad), but the modern conjugation is weak and abided is used. The present-to-preterite vowel change is consistent with an Old English class I strong verb (ride/rode, etc.). Meaning "habitual residence" is first attested 1570s.
word-forming element meaning "killer," from French -cide, from Latin -cida "cutter, killer, slayer," from -cidere, combining form of caedere "to strike down, chop, beat, hew, fell, slay," from Proto-Italic *kaid-o-, from PIE root *kae-id- "to strike." For Latin vowel change, see acquisition. The element also can represent "killing," from French -cide, from Latin -cidium "a cutting, a killing."
fifteenth letter of the alphabet, from a character that in Phoenician was called 'ain (literally "eye") and represented "a very peculiar and to us unpronounceable guttural" [Century Dictionary]. The Greeks also lacked the sound, so when they adopted the Phoenician letters they arbitrarily changed O's value to a vowel. (Thus there is no grounds for the belief that the form of the letter represents the shape of the mouth in pronouncing it.) The Greeks later added a special character for "long" O (omega), and the original became "little o" (omicron).
In Middle English and later colloquial use, o or o' can be an abbreviation of on or of, and is still literary in some words (o'clock, Jack-o'-lantern, tam-o'-shanter, cat-o'-nine-tails, will-o'-the-wisp, etc.).
O' the common prefix in Irish surnames is from Irish ó, ua (Old Irish au, ui) "descendant."
The "connective" -o- is the usual connecting vowel in compounds taken or formed from Greek, where it often is the vowel in the stem. "[I]t is affixed, not only to terms of Greek origin, but also to those derived from Latin (Latin compounds of which would have been formed with the L. connecting or reduced thematic vowel, -i), especially when compounds are wanted with a sense that Latin composition, even if possible, would not warrant, but which would be authorized by the principles of Greek composition." [OED]
As "zero" in Arabic numerals it is attested from c. 1600, from the similarity of shape. Similarly the O blood type (1926) was originally "zero," denoting the absence of A and B agglutinogens.
As a gauge of track in model railroads, by 1905. For o as an interjection of fear, surprise, joy, etc., see oh.
The use of the colloquial or slang -o suffix in wino, ammo, combo, kiddo, the names of the Marx Brothers, etc., "is widespread in English-speaking countries but nowhere more so than in Australia" [OED].