The Collaborative International Dictionary of English v.0.48:
Peeress \Peer"ess\, n. The wife of a peer; a woman ennobled in her own right, or by right of marriage. [1913 Webster] PeerieWordNet (r) 3.0 (2006):
peeress n 1: a woman of the peerage in Britain [syn: Lady, noblewoman, peeress] [ant: Lord, noble, nobleman]Bouvier's Law Dictionary, Revised 6th Ed (1856):
PEERESS. A noblewoman, the wife of a peer.