The word “liase,” meaning “to establish a working relationship based on a matter of mutual concern,” came about in the 1920s in a military context, as a back-formation of the word “liaison.” “Liaison” can be traced back to the mid-17th century, where its first usage was in the kitchen. It comes from the French word “lier,” meaning “to bind.” A liaison was the thickening agent of a sauce, often based on egg yolks.