Fi"at (?), n. [L., let it be done, 3d
pers. sing., subj. pres., fr. fieri, used as pass. of
facere to make. Cf. Be.] 1. An
authoritative command or order to do something; an effectual
decree.
His fiat laid the corner stone.
Willis.
2. (Eng. Law) (a) A
warrant of a judge for certain processes. (b)
An authority for certain proceedings given by the Lord
Chancellor's signature.
Fiat money, irredeemable paper currency, not
resting on a specie basis, but deriving its purchasing power from the
declaratory fiat of the government issuing it.