Pronunciation: (sing'gul-tun), [key]
1. a person or thing occurring singly, esp. an individual set apart from others: a research program involving twins and singletons.
2. Cards.a card that is the only one of a suit in a hand.
3. Math.a set consisting of one given element.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.