Ventral

Ventral refers to the underside of a body and the term is commonly used in defining the bottom of a starship. This nomenclature is necessary while functioning in the three dimensions of space.

The ventral plating team stated they would be completed with their work on in three days in April 2151. 

During Shinzon's attack on the USS Enterprise (NCC-1701-E) in 2379, all ventral phasers were fired in a single maneuver. In addition, the starship's ventral shielding failed on deck 29 as the result of a focused attack.