Cachet \Cach"et\, n. [F. fr. cacher to hide.] A seal, as of a letter. {Lettre de cachet} [F.], a sealed letter, especially a letter or missive emanating from the sovereign; -- much used in France before the Revolution as an arbitrary order of imprisonment.
lettre de cachet n : a warrant formerly issued by a French king who could warrant imprisonment or death in a signed letter under his seal [syn: {cachet}]