basis

basis (noun; plural bases; Latin basis, base): 1. A general term for the base of any appendage.

2. (Arthropoda: Crustacea) a. A protopod segment adjoining the coxa and carrying the exopod and endopod distally. b. The basipodite. c. A basal calcareous or membranous plate functioning in anchorage of sessile barnacles to the substrate.