Borrowed from French châtelaine, the feminine form of châtelain (“castle-keeper, castellan; one living in a castle”), from Medieval Latin castellanus (“occupants of a castle”), from castellum (“castle, fort”) (diminutive of castrum (“castle, fort”), from Proto-Indo-European *ḱes- (“to cut off, separate”)) + -ānus (“suffix meaning ‘of or pertaining to’”).
chatelaine (plural chatelaines)
- (dated) The mistress of a castle or large household. [from mid 19th c.]
- (historical) A chain or clasp worn at the waist by women with handkerchief, keys, etc., attached, supposed to resemble the chain of keys once worn by medieval chatelaines.
- A similar thing in miniature attached to a watchchain.