Definition of "tubercle"

(anatomy) A round nodule, small eminence, or warty outgrowth, especially those found on bones for the attachment of a muscle or ligament or small elevations on the surface of a tooth.  examples

(botany) A small rounded wartlike protuberance of the roots of some leguminous plants; the lip of certain orchids, cacti.  examples

(pathology) A small rounded nodule forming the characteristic lesion of tuberculosis.