lady

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A woman of high social standing or refinement, especially when viewed as dignified or well-mannered.
• noun A woman who is the head of a household.
• noun A woman, especially when spoken of or to in a polite way.
• noun Used as a form of address for a woman, often with sarcasm or irritation.
• noun A woman who is the object of romantic or chivalrous love.
• noun Informal A wife or girlfriend.
• noun A lady in waiting.
• noun A general feminine title of nobility and other rank, specifically as the title for the wife or widow of a knight or baronet.
• noun Used as a form of address for a woman of high rank, especially for a marchioness, countess, viscountess, baroness, or baronetess.
• noun The Virgin Mary. Usually used with Our.

from The Century Dictionary.

• noun In astrology, a term designating the planet Venus when in the circumstances under which, if a masculine planet, she would be termed lord: as, lady of the ascendant.
• noun A woman who has authority over a manor or family; the mistress of a household: the feminine correlative to lord.
• noun Specifically, in Great Britain, the proper title of any woman whose husband is higher in rank than baronet or knight, or who is the daughter of a nobleman not lower than an earl, though the title is given by courtesy also to the wives of baronets and knights; also, the feminine title correlative originally to Lord, and now also to Sir.
• noun In the days of chivalry, the woman chosen by a knight or squire as the object of his especial service, his feats of arms being done in her honor, and his success ascribed to her influence.
• noun A woman of good family and of established social position, or one accepted as such: a restricted sense correlative to gentleman in like use.
• noun A woman of good breeding, education, and refinement of mind and manner: a general sense correlative to gentleman in like use: in common speech used indiscriminately as a synonym for woman (a use generally vulgar, and to be avoided except in address). See gentleman, 4.
• noun A wife; a man's spouse: used in this sense always with direct reference to the husband: as, John Smith and lady.
• noun A sweetheart.
• noun A slate measuring about 16 inches long by 10 broad.
• noun The calcareous apparatus in the cardiac part of the stomach of the lobster, the function of which is the trituration of the food.
• Of a lady; ladylike.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Belonging or becoming to a lady; ladylike.
• noun A woman who looks after the domestic affairs of a family; a mistress; the female head of a household.
• noun A woman having proprietary rights or authority; mistress; -- a feminine correlative of lord.
• noun A woman to whom the particular homage of a knight was paid; a woman to whom one is devoted or bound; a sweetheart.
• noun A woman of social distinction or position. In England, a title prefixed to the name of any woman whose husband is not of lower rank than a baron, or whose father was a nobleman not lower than an earl. The wife of a baronet or knight has the title of Lady by courtesy, but not by right.
• noun A woman of refined or gentle manners; a well-bred woman; -- the feminine correlative of gentleman.
• noun A wife; -- not now in approved usage.
• noun Any woman; ; also used in combination.
• noun (Zoöl.) The triturating apparatus in the stomach of a lobster; -- so called from a fancied resemblance to a seated female figure. It consists of calcareous plates.
• noun a man who affects the society of ladies.
• noun an altar in a lady chapel.
• noun a chapel dedicated to the Virgin Mary.
• noun the court of a lady of the manor.
• noun (Zoöl.) a handsomely spotted swimming crab (Platyonichus ocellatus) very common on the sandy shores of the Atlantic coast of the United States.
• noun (Bot.) See Female fern, under Female, and Illust. of Fern.
• noun a lady of the queen's household, appointed to wait upon or attend the queen.
• noun a Mass said in honor of the Virgin Mary.
• noun a lady having jurisdiction of a manor; also, the wife of a manor lord.
• noun a maidservant who dresses and waits upon a lady.
• noun the Virgin Mary.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun historical The mistress of a household.
• noun A woman of breeding or higher class, a woman of authority.
• noun The feminine of lord.
• noun A title for someone married to a lord.
• noun A title for somebody married to a gentleman.
• noun A title that can be used instead of the formal terms of marchioness, countess, viscountess or baroness.