Old English etere "one who eats," especially a servant or retainer, agent noun from eat (v.)). From 17c. in compounds with various objects or substances eaten.
Entries linking to eater
eat v.
Old English etan (class V strong verb; past tense æt, past participle eten) "to consume food, devour, consume," from Proto-Germanic *etan (source also of Old Frisian ita, Old Saxon etan, Middle Dutch eten, Dutch eten, Old High German ezzan, German essen, Old Norse eta, Gothic itan), from PIE root *ed- "to eat."
Transferred sense of "corrode, wear away, consume, waste" is from 1550s. Meaning "to preoccupy, engross" (as in what's eating you?) first recorded 1893. Slang sexual sense of "do cunnilingus on" is first recorded 1927. The slang phrase eat one's words "retract, take back what one has uttered" is from 1570s; to eat one's heart out is from 1590s; for eat one's hat, see hat. Eat-in (adj.) in reference to kitchens is from 1955. To eat out "dine away from home" is from 1930.
beef-eater n.
also beefeater, c. 1600 as a general contemptuous term for a well-fed menial; specifically as "warder of the Tower of London" from 1670s; the notion is of "one who eats (another's) beef" (see eater, and compare Old English hlaf-æta "servant," literally "loaf-eater").