the later Romans evidently found words beginning in sc-, sp-, st- difficult or unpleasant to pronounce; in Late Latin forms begin to emerge in i- (such as ispatium, ispiritu), and from 5c. this shifted to e-. The development was carried into the Romanic languages, especially Old French, and the French words were modified further after 15c. by natural loss of -s- (the suppression being marked by an acute accent on the e-), while in other cases the word was formally corrected back to the Latin spelling (for example spécial). Hence French état for Old French estat for Latin status, etc. It also affected Romanic borrowings from Germanic (such as espy, eschew).
A different e- is a reduced form of Latin ex- before consonants (see ex-), and the e- in enough is an unfelt survival of an Old English alternative form of ge-.
bacteria inhabiting the gut of man and animals, by 1921, short for Escherichia coli (1911), named for German physician Theodor Escherich (1857-1911) with Latin genitive of colon "colon" (see colon (n.2)).
motto of the United States, being one nation formed by uniting several states, 1782, Latin, from e "out of" (see ex-); ablative plural of plus "more" (see plus (n.)); neuter of unus "one" (from PIE root *oi-no- "one, unique"). Not found in classical Latin, though a variant of the phrase appears in Virgil (color est e pluribus unum); the full phrase was the motto of the popular Gentleman's Magazine from 1731 into the 1750s.
common digraph introduced early 16c., originally having the sound of long "a" and meant to distinguish words spelled -e- or -ee- with that sound from those with the sound of long "e"; for example break, great. Since c. 1700, the sound in some of them has drifted to long "e" (read, hear) or sometimes short "e" (bread, wealth).
the usual Old English word for "river, running water" (still in use in Lancashire, according to OED), from Proto-Germanic *ahwo- (source also of Old Frisian a,Old Saxon aha,Old High German aha,German ahe-,Old Dutch aha,Old Norse "water"), from PIE root *ekweh- "water" (see aqua-). "The standard word in place-names for river denoting a watercourse of greater size than a broc or a burna" [Cambridge Dictionary of English Place-Names].
Old English ælc (n., pron., adj.) "any, all, every, each (one)," short for a-gelic "ever alike," from a "ever" (see aye (adv.)) + gelic "alike" (see like (adj.)). From a common West Germanic expression *aina-galīk (source also of Dutch elk, Old Frisian ellik, Old High German iogilih, German jeglich "each, every"). Originally used as we now use every (which is a compound of each) or all; modern use is by influence of Latin quisque. Modern spelling appeared late 1500s. Also see ilk, such, which.
late 13c., "strenuous, ardent, fierce, angry," from Old French aigre "sour, acid; harsh, bitter, rough; eager greedy; lively, active, forceful," from Vulgar Latin *acrus (source also of Italian agro, Spanish agrio), from Latin acer "keen, sharp, pointed, piercing; acute, ardent, zealous" (from PIE root *ak- "be sharp, rise (out) to a point, pierce").
Meaning "full of keen desire" (early 14c.) seems to be peculiar to English. The English word kept a secondary meaning of "pungent, sharp-edged" till 19c. (as in Shakespeare's "The bitter clamour of two eager tongues," in "Richard II"). Related: Eagerly; eagerness. Eager beaver "glutton for work" [OED] is from 1943, U.S. armed forces slang.
"very large diurnal raptorial bird of the genus Aquila," mid-14c., from Old French egle, from Old Provençal aigla, from Latin aquila "black eagle," fem. of aquilus "eagle," often explained as "the dark colored" (bird); see aquiline. The native term was erne.
Golf score sense is by 1908 (according to old golf sources, because it "soars higher" than a birdie). As the name of a U.S. $10 coin minted from 1792 to 1933, established in the 1786 resolution for a new monetary system (but at first only the desperately needed small copper coins were minted). The figurative eagle-eyed "sharp-sighted" (like an eagle) is attested from c. 1600.
"a young eagle," 1570s, from French aiglette, diminutive of aigle (see eagle).