old maid

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

• noun Offensive Used as a disparaging term for a woman who is no longer young and has not married.
• noun Informal A person regarded as being primly fastidious.
• noun A card game in which the player who holds a designated card at the end is the loser.
• noun The loser of this game.

from The Century Dictionary.

• noun The house-or garden-plant Vinca rosea.
• noun A gaping clam: same as gaper, 4.

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

• noun pejorative An old woman who has never married; a spinster.
• noun A particular kind of periwinkle.
• noun A particular kind of zinnia.
• noun An unpopped kernel in a batch of popped popcorn kernels.
• noun A card game in which cards must be paired and one undesirable card is designated "old maid".
• noun An unpaired card in that game.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a card game using a pack of cards from which one queen has been removed; players match cards and the player holding the unmatched queen at the end of the game is the loser (or `old maid')
• noun an elderly unmarried woman
• noun the loser in a game of old maid
• noun any of various plants of the genus Zinnia cultivated for their variously and brightly colored flower heads
• noun commonly cultivated Old World woody herb having large pinkish to red flowers