The Collaborative International Dictionary of English v.0.48:

Milady \Mi*la"dy\, n. [F., fr. English.]
   Lit., my lady; hence (as used on the Continent), an English
   noblewoman or gentlewoman.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Milady
    n 1: an English noblewoman

Moby Thesaurus II by Grady Ward, 1.0:

46 Moby Thesaurus words for "milady":
   Eminence, Eve, Frau, Grace, Her Excellency, Her Highness,
   Her Ladyship, Her Majesty, Highness, His Lordship, His Majesty,
   Honor, Imperial Highness, Imperial Majesty, Lady, Ladyship, Lord,
   Lordship, Majesty, My Lady, My Lord, Reverence, Royal Highness,
   Royal Majesty, Serene Highness, Worship, Your Lordship, dame,
   daughter of Eve, distaff, domina, donna, dowager, femme, frow,
   gentlewoman, girl, lady, lass, matron, milord, squaw, vrouw,
   wahine, weaker vessel, woman