brewster (n.)

Old English -istre, from Proto-Germanic *-istrijon, feminine agent suffix used as the equivalent of masculine -ere (see -er (1)). Also used in Middle English to form nouns of action (meaning "a person who ...") without regard for gender.

The genderless agent noun use apparently was a broader application of the original feminine suffix, beginning in the north of England, but linguists disagree over whether this indicates female domination of weaving and baking trades, as represented in surnames such as Webster, Baxter, Brewster, etc. (though spinster probably carries an originally female ending).

Also compare whitester "one who bleaches cloth;" kempster (c. 1400; Halliwell has it as kembster) "woman who cleans wool." Chaucer ("Merchant's Tale") has chidester "an angry woman." In Modern English, the suffix has been productive in forming derivative nouns (gamester,roadster, punster, rodster "angler," etc.; the 17c. had scoldster).

mid-14c., "female spinner of thread," from Middle English spinnen "spin fibers into thread" (see spin (v.)) + -stere, feminine suffix (see -ster). Unmarried women were supposed to occupy themselves with spinning, hence the word came to be "the legal designation in England of all unmarried women from a viscount's daughter downward" [Century Dictionary] in documents from 1600s to early 1900s, and by 1719 the word was being used generically for "woman still unmarried and beyond the usual age for it."

Spinster, a terme, or an addition in our Common Law, onely added in Obligations, Euidences, and Writings, vnto maids vnmarried. [John Minsheu, "Ductor in Linguas," 1617]

Strictly in reference to those who spin, spinster also was used of both sexes (compare webster, Baxter, brewster) and so a double-feminine form emerged, spinstress "a female spinner" (1640s), which by 1716 also was being used for "a maiden lady." Related: Spinsterhood.