commodore UK /ˈkɒm.ə.dɔː/US /ˈkɑ.mə.dɔɹ/ noun8 •A naval officer holding a rank between captain and rear admiral. •(US) A rear admiral (lower half). •Ellipsis of commodore admiral. •The president of a yacht club. •A (temporary) commander over a collection of ships who is not an admiral. •The leading ship in a fleet of merchantmen. •A yacht-club president's vessel in a regatta. •Any of various nymphalid butterflies of the Asian genus Parasarpa. formscommodores