Pronunciation: (pos'ul-kyOO"), [key]
—pl. POSSLQs, POSSLQ's.
either of two persons, one of each sex, who share living quarters but are not related by blood, marriage, or adoption: a categorization used by the U.S. Census Bureau.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.