Source : Webster's Revised Unabridged Dictionary (1913)

Necessarian \Nec`es*sa"ri*an\, n. [Cf. F. n['e]cessarien. See
   {Mecessary}.]
   An advocate of the doctrine of philosophical necessity; a
   nacessitarian.

Necessarian \Nec`es*sa"ri*an\, a.
   Of or pertaining to necessarianism.