chatelaine (n.) Look up chatelaine at Dictionary.com
1845, from French châtelaine "a female castellan; wife of a castellan; mistress of a castle or country house;" fem. of châtelain, from Old French chastelain "owner and lord of a castle, castellan, nobleman," from chastel (see chateau). In fashion, as a type of ornamental belt, from 1851; supposed to resemble a chain of keys.