Mammillary \Mam"mil*la*ry\, a. [Cf. F. mammilaire. See {Mammilla}.] 1. Of or pertaining to the mammilla, or nipple, or to the breast; resembling a mammilla; mammilloid. [1913 Webster] 2. (Min.) Composed of convex convex concretions, somewhat resembling the breasts in form; studded with small mammiform protuberances. [1913 Webster] Mammillate