- liaison (adj.)
- 1648, from Fr. liaison "a union, a binding together," from L.L. ligationem (nom. ligatio) "a binding," from L. ligatus, pp. of ligare "to bind" (see ligament). Originally a cookery term for a thickening agent for sauces. Sense of "intimate relations" is from 1806. Military sense of "cooperation between branches, allies, etc." is from 1816. Back-formed verb liaise is attested from 1928. The noun meaning "one who is concerned with liaison of units, etc." is short for liaison officer.