earnest n[Anglo-French ernes(t) erles , alteration of Old French erres , plural of erre pledge, earnest, alteration of Latin arra , short for arrabo , from Greek arrhabōn , of Semitic origin]
: something of value given by a buyer to a seller to bind a bargain
Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.