Sĕp'tum, n.

noun

Sĕp'tum, n.; pl. SĔP'TȦ. [Lat., an inclosure, hedge, fence, from sepire, to hedge in, to inclose.] A wall separating two cavities; a partition; specifically, (a.) (Bot.) A partition that separates the cells of the fruit. (b.) (Anat.) A partition which separates two cavities.

A cross-section of a citrus fruit, with its segments and seeds visible.