Source : Webster's Revised Unabridged Dictionary (1913)

Mammillate \Mam"mil*late\, Mammillated \Mam"mil*la`ted\, a. [See
   {Mammilla}.]
   1. Having small nipples, or small protuberances like nipples
      or mamm[ae].

   2. (Zo["o]l.) Bounded like a nipple; -- said of the apex of
      some shells.