abdominal UK /æbˈdɒm.ə.nl̩/US /æbˈdɑm.ə.nl̩/adjective 5noun 2forms 3 adjective5 •Of or pertaining to the abdomen; ventral.abdominal muscles •Ventral, in describing a fin. •Having the ventral fins under the abdomen and behind the pectoral fins. •(no longer used) Belonging to the order Abdominales of fish. •(humorous, no longer used) Characterized by or possessing a large abdomen; corpulent, pot-bellied.The moment they had passed, the pikes clashed together horizontally to bar the gateway, and all but pinned an abdominal citizen that sought to wedge in along with them. noun2 •[usually plural] (informal) An abdominal muscle. •(no longer used) A fish of the order Abdominales. formsabdominals · more abdominal · most abdominal