Source : Webster's Revised Unabridged Dictionary (1913)

Thuja \Thu"ja\, n. [NL., from Gr. ? an African tree with
   sweet-smelling wood.] (Bot.)
   A genus of evergreen trees, thickly branched, remarkable for
   the distichous arrangement of their branches, and having
   scalelike, closely imbricated, or compressed leaves. [Written
   also {thuya}.] See {Thyine wood}.

   Note: {Thuja occidentalis} is the {Arbor vit[ae]} of the
         Eastern and Northern United States. {T. gigantea} of
         North-waetern America is a very large tree, there
         called {red cedar}, and {canoe cedar}, and furnishes a
         useful timber.

Arbor vitae \Ar"bor vi"t[ae]\ [L., tree of life.]
   1. (Bot.) An evergreen tree of the cypress tribe, genus
      {Thuja}. The American species is the {T. occidentalis}.

   2. (Anat.) The treelike disposition of the gray and white
      nerve tissues in the cerebellum, as seen in a vertical
      section.