1.In medical language a tubercle is a round nodule or small eminence found on numerous bones.

An alternate meaning is a small rounded nodule forming the characteristic lesion of tuberculosis.

2. (Botany) A tubercle is a small warty outgrowth, such as can be seen on certain leaf surfaces or on the lip of certain orchids, such as the tubercled orchid (Platanthera flava). Tubercles are also found on cacti, such as the Mammillaria compressa, as a much-enlarged leaf base.