Online Etymology Dictionary

'em: Middle English, now taken as a colloquial abbreviation of them, but originally a form of hem, dative and accusative of the third person plural pronoun.
-ean: variant of -an after names ending in -ea, -es, -eus.
-ectomy: word-forming element meaning "surgical removal," from Greek -ektomia "a cutting out of," from ektemnein "to cut out," from ek "out" (see ex-) + temnein "to cut" (see tome).
-ed: pp. suffix of weak verbs, from Old English -ed, -ad. --od (leveled to -ed in Middle English), from Proto-Germanic *-do- (cf. Old High German -ta, German -t, Old Norse -þa, Gothic -da, -þs), from PIE *-to- (cf. Sanskrit -tah, Greek -tos, Latin -tus).

Originally fully pronounced, as still in beloved (which, with blessed, accursed, and a few others retains the full pronunciation through liturgical readings). In 16c.-18c. often written -t when so pronounced (usually after a consonant or short vowel), and still so where a long vowel in the stem is short in the pp. (e.g. crept, slept, etc.). In some older words both forms exist, with different shades of meaning, e.g. gilded/gilt, burned/burnt.
-ee: word-forming element in legal English (and in imitation of it), representing the Anglo-French -é ending of pps. used as nouns. As these sometimes were coupled with agent nouns in -or, the two suffixes came to be used as a pair to denote the initiator and the recipient of an action.
-een: anglicized form of French -in, -ine, ultimately from Latin -inus -ina.
-eer: suffix meaning "one who" (operates, produces, deals in); anglicized form of French -ier, from Latin -arius, -iarius; cf. -ary.
-ella: diminutive suffix, from Latin -ella, fem. of -ellus.
-eme: in linguistics, noted as an active suffix and word-formation element from 1953; from French -ème "unit, sound," from phonème (see phoneme).
-emia: word-forming element in medicine meaning "condition of the blood," Modern Latin comb. form of Greek haima (genitive haimatos) "blood," possibly from PIE root *sai- "thick liquid."
-en (1): word-forming element making verbs (e.g. darken, weaken) from adjectives or from nouns, from Old English -nian, from Proto-Germanic *-inojan (cf. Old Norse -na), from PIE adjectival suffix *-no-. Most active in Middle English.
-en (2): suffix added to nouns to produce adjectives meaning "made of, of the nature of" (e.g. golden, oaken), corresponding to Latin -ine. Common in Old and Middle English, surviving words with it now are largely discarded in everyday use and the simple form of the noun serves as an adjective as well.
-ence: see -ance.
-ency: word-forming element denoting quality or state, from Latin -entia. Derivatively identical with -ence.
-ene: hydrocarbon suffix, from Greek name-forming suffic -ene; it has no real meaning in itself; probably abstracted mid-19c. from methylene (1834). Put in systematic use by Hofmann (1865). "The breakdown of methylene into methyl and -ene, and the identification of the last syllable of methyl with the general suffix -ly, led to the use of meth- as a separate combining-element, as, for example, in methane, methacrylic [Flood].
-ent: suffix forming adjectives from nouns or verbs, from French -ent and directly from Latin -entem, present participle ending of verbs in -ere/-ire. Old French changed many to -ant but after c.1500 some of these in English were changed back to what was supposed to be correct Latin.
-er (1): English agent noun ending, corresponding to Latin -or. In native words it represents Old English -ere (Old Northumbrian also -are) "man who has to do with," from West Germanic *-ari (cf. German -er, Swedish -are, Danish -ere), from Proto-Germanic *-arjoz. Some believe this root is identical with, and perhaps a borrowing of, Latin -arius.

In words of Latin origin, verbs derived from pp. stems of Latin ones (including most verbs in -ate) usually take the Latin ending -or, as do Latin verbs that passed through French (e.g. governor), but there are many exceptions (eraser, laborer, promoter, deserter, sailor, bachelor), some of which were conformed from Latin to English in late Middle English.

The use of -or and -ee in legal language (e.g. lessor/lessee) to distinguish actors and recipients of action has given the -or ending a tinge of professionalism, and this makes it useful in doubling words that have both a professional and non-professional sense (e.g. advisor/adviser, conductor/conducter, incubator/incubater, elevator/elevater).
-er (2): comparative suffix, from Old English -ra (masc.), -re (fem., neuter), from Proto-Germanic *-izon, *-ozon (cf. Gothic -iza, Old Saxon -iro, Old Norse -ri, Old High German -iro, German -er), originally also with umlaut change in stem, but this was mostly lost in Old English by historical times and has now vanished (except in better and elder).
For most comparatives of one or two syllables, use of -er seems to be fading as the oral element in our society relies on more before adjectives to express the comparative; thus prettier is more pretty, cooler is more cool [Barnhart].
-er (3): suffix used to make jocular or familiar formations from common or proper names (soccer being one), first attested 1860s, English schoolboy slang, "Introduced from Rugby School into Oxford University slang, orig. at University College, in Michaelmas Term, 1875" [OED, with unusual precision].
-ery: word-forming element making nouns meaning "place for, art of, condition of, quantity of," from Middle English -erie, from Latin -arius.
-escence: word-forming element meaning "process or state of being," from Latin -escentia, from -escentem (see -escent).
-escent: word-forming element meaning "beginning, becoming, tending to be," from Latin -escentem (nominative -escens), ending of present participles of verbs in -escere.
-ese: word-forming element from Old French -eis (Modern French -ois, -ais), from Vulgar Latin, from Latin -ensem, -ensis "belonging to" or "originating in."
-esque: word-forming element meaning "resembling or suggesting the style of," from French -esque "like, in the manner of," from Italian -esco, like Medieval Latin -iscus from a Germanic source (cf. Old High German -isc, German -isch, English -ish; see -ish).
-ess: fem. suffix, from French -esse, from Late Latin -issa, from Greek -issa (cognate with Old English fem. agent suffix -icge); rare in classical Greek but more common later, in diakonissa "deaconess" and other Church terms picked up by Latin.
-etic: word-forming element meaning "pertaining to," from Greek -etikos, adjectival suffix for nouns ending in -esis.
-ette: diminutive formation, from Old French -ette (fem.), used indiscriminately in Old French with masculine form -et. As a general rule, older words borrowed from French have -et in English, while ones taken in since 17c. have -ette. In use with native words since 20c., especially among persons who coin new product names, who tend to give it a sense of "imitation." Also in words like sermonette, which, OED remarks, "can scarcely be said to be in good use, though often met with in newspapers."
e'en: variant spelling of even, now archaic or poetic.
e'er: variant spelling of ever, now archaic or poetic.
e-commerce (n.): by 1998, from electronic (cf. e-mail) + commerce.
e-mail: 1982, short for electronic mail (1977; see electronic + mail (n.1)); this led to the contemptuous application of snail mail (1983) to the old system.
Even aerial navigation in 1999 was found too slow to convey and deliver the mails. The pneumatic tube system was even swifter, and with such facilities at hand it is not surprising that people in San Francisco received four daily editions of the Manhattan journals, although the distance between Sandy Hook and the Golden Gate is a matter of 3,600 miles. ["Looking Forward," Arthur Bird, 1899]
Associated Press style guide collapsed it to email 2011.
E. coli (n.): "bacteria inhabiting the gut of man and animals," short for Escherichia coli, named for German physician Theodor Escherich (1857-1911) + Latin genitive of colon "colon" (see colon (n.2)).
e.g.: abbreviation of Latin exemplia gratia "for the sake of example."
e.t.a.: abbreviation of estimated time (of) arrival, first attested 1939.
ea (n.): the usual Old English word for "river, running water;" still in use in Lancashire. 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].
each: Old English ælc "any, all, every, each (one), short for a-gelic "ever alike," from a "ever" (see aye (2)) + gelic "alike" (see like (adj.)).

From a common West Germanic expression *aiwo galika (cf. 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 cf. ilk, which.
each other: reciprocal pronoun, originally in late Old English a phrase, with each as the subject and other inflected (as it were "each to other," "each from other," etc.).
eager (adj.): late 13c., "strenuous, ardent, fierce, angry," from Old French aigre "sour, acid; harsh, bitter, rough; eager greedy; lively, active, forceful," from Latin acrem (nominative acer) "keen, sharp, pointed, piercing; acute, ardent, zealous" (see acrid).

Meaning "full of keen desire" (early 14c.) seems to be peculiar to English. The English word kept an alternative meaning of "pungent, sharp-edged" till 19c. (e.g. Shakespeare's "The bitter clamour of two eager tongues," in "Richard II"). Related: Eagerly; eagerness.
eagle (n.): mid-14c., from Old French egle, from Old Provençal aigla, from Latin aquila "black eagle," fem. of aquilus, often explained as "dark colored" (bird); see aquiline. The native term was erne. Golf score sense is first recorded by 1908 (according to old golf sources, because it "soars higher" than a birdie). The figurative eagle-eyed is attested from c.1600.
Eames: 1946, type of modern office chair, named for U.S. architect and designer Charles Eames (1907-1978).
ear (n.1): "organ of hearing," Old English eare "ear," from Proto-Germanic *auzon (cf. Old Norse eyra, Danish øre, Old Frisian are, Old Saxon ore, Middle Dutch ore, Dutch oor, Old High German ora, German Ohr, Gothic auso), from PIE *ous- with a sense of "perception" (cf. Greek aus, Latin auris, Lithuanian ausis, Old Church Slavonic ucho, Old Irish au "ear," Avestan usi "the two ears").

The belief that itching or burning ears means someone is talking about you is mentioned in Pliny's "Natural History" (77 C.E.). Until at least the 1880s, even some medical men still believed piercing the ear lobes improved one's eyesight. Meaning "handle of a pitcher" is mid-15c. (but cf. Old English earde "having a handle"). To be wet behind the ears "naive" is implied from 1914. Phrase walls have ears attested from 1610s. Ear-bash (v.) is Australian slang (1944) for "to talk inordinately" (to someone).
ear (n.2): "grain part of corn," from Old English ear (West Saxon), æher (Northumbrian) "spike, ear of grain," from Proto-Germanic *akhaz (genitive *akhizaz; cf. Dutch aar, Old High German ehir, German Ähre, Old Norse ax, Gothic ahs "ear of corn"), from PIE root *ak- "sharp, pointed" (cf. Latin acus "husk of corn," Greek akoste "barley;" see acrid).
earache (n.): 1789, from ear (n.1) + ache (n.).
eardrum (n.): 1640s, from ear (n.1) + drum (n.).
earful (n.): "a piece of one's mind," 1917, from ear (n.1) + -ful.
earl (n.): Old English eorl "brave man, warrior, leader, chief" (contrasted with ceorl "churl"), from Proto-Germanic *erlo-z, of uncertain origin.

In Anglo-Saxon poetry, "a warrior, a brave man;" in later Old English, "nobleman," especially a Danish under-king (equivalent of cognate Old Norse jarl), then one of the viceroys under the Danish dynasty in England. After 1066 adopted as the equivalent of Latin comes (see count (n.)).
earldom (n.): early 12c., from earl + -dom.
earlobe (n.): by 1786, from ear (n.1) + lobe. Earlier was ear lap (Old English had earlæppa "external ear").
early (adv.): Old English ærlic "early," from ær "soon, ere" (see ere) + -lice, adverbial suffix (see -ly (2)). Cf. Old Norse arliga "early." The early bird of the proverb is from 1670s. Related: Earlier; earliest.
earmark (n.): late 15c., from ear (n.1) + mark (n.1). Originally a cut or mark in the ear of sheep and cattle, serving as a sign of ownership (also a punishment of certain criminals); first recorded 1570s in figurative sense "stamp of ownership."