tuba UK /ˈtjuː.bə/US /ˈtu.bə/noun 5/tuˈbə/ noun 1forms 2 noun5 •A large brass musical instrument, usually in the bass range, played through a vibration of the lips upon the mouthpiece and fingering of the keys.One version of the large tuba, popular in marching bands, is called a sousaphone in honor of bandsman John Philip Sousa. — 1990 •A type of Roman military trumpet, distinct from the modern tuba.This depicts trumpet blowing angels gripping instruments, of the Roman tubae variety, halfway down with the right hand, the left hand covering their mouth and the mouthpiece. — 1986 •A large reed stop in organs. •A tube or tubular organ. •A Malayan plant whose roots are a significant source of rotenone, Derris malaccensis. tuba /tuˈbə/ noun1 •(Philippines) A reddish palm wine made from coconut or nipa sap. formstubae · tubas