\U`ni*ta"ri*an\, n. [Cf. F. unitaire, unitairien, NL.
unitarius. See {Unity}.]
1. (Theol.) One who denies the doctrine of the Trinity,
   believing that God exists only in one person; a
   unipersonalist; also, one of a denomination of Christians
   holding this belief.
2. One who rejects the principle of dualism.
3. A monotheist. [R.] --Fleming.

\U`ni*ta"ri*an\, a.
Of or pertaining to Unitarians, or their doctrines.