Ventral: pertaining to the lower side of the body.

Ventral fin: paired fins situated near the ventral midline, absent in some fishes.

In order not to confuse the paired fins located at the ventral side of a fish with the anal fin, which is also situated there, the term "pelvic fin" is used. In fin formulas, however, the pelvic fin is designated by the letter V, because the pectoral fin is defined by the letter P. Fin-ray counts of both P and V are of little meaning to lower taxa, they may be useful in the identification of orders.

Alternative form for ventral : Ventral fin.