Source : Webster's Revised Unabridged Dictionary (1913)

Ambitus \Am"bi*tus\ ([a^]m"b[i^]*t[u^]s), n. [L. See {Ambit},
   {Ambition}.]
   1. The exterior edge or border of a thing, as the border of a
      leaf, or the outline of a bivalve shell.

   2. (Rom. Antiq.) A canvassing for votes.