STER, in composition, is from the Sax. Steora, a director. See Steer. It seems primarily to have signified chief, principal or director, as in the Latin Minister, chief servant; but in other words, as in spinster, we do not recognize the sense of chief, but merely that of a person who carries on the business of spinning.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI