n. 1 communication or cooperation, esp. between military forces or units. 2 an illicit sexual relationship. 3 the binding or thickening agent of a sauce. 4 the sounding of an ordinarily silent final consonant before a word beginning with a vowel (or a mute h in French). liaison officer an officer acting as a link between allied forces or units of the same force.
[ F f. lier bind f. L ligare ]