venˈtral adjective

1. Of the belly
2. On the upper side or towards the axis (botany)
3. On the side normally turned towards the ground, opp to dorsal or neural (zoology)

A ventral fin

venˈtrally adverb

venˈtricose or (rare) venˈtricous adjective

1. Distended or swollen in the middle, at the side, or round the base (botany, zoology)
2. Having a prominent or swollen belly

ventral fin noun

Either of the paired fins on the belly of a fish

ventral tank noun (aeronautics)

An auxiliary fuel tank, fixed or able to be jettisoned, mounted externally under the fuselage (also belly tank)