Early use of the word referred to the mistress of a private household, the OldEngl. hlaefdige; it was also the female equivalent of a lord and title of the king's wife in the 10c and 11c. Later, 'lady' acquired the poetic sense of a woman who was the object of chivalric attentions, the object of *courtly love in the songs of troubadours. Its origin is less refined, as the OldEngl. word hlaefdige < hlaf = a loaf + daege = a female servant; a lady was one who kneaded bread dough. -
Cf. Lord
Dictionary of Medieval Terms and Phrases. Christopher Coredon with Ann Williams.