TUBA

n. large brass wind instrument having valves and producing tones in the low range; powerful organ reed stop; ancient Roman trumpet (Musical)

The tuba is the largest and lowest pitched of brass instruments. Sound is produced by vibrating or "buzzing" the lips into a large cupped mouthpiece. It is one of the most recent additions to the modern symphony orchestra, first appearing in the mid-19th century, when it largely replaced the ophicleide.
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Noun
1. the lowest brass wind instrument
(synonym) bass horn, sousaphone
(hypernym) brass
(hyponym) euphonium

n. tuba, large brass wind instrument having valves and producing tones in the low range (Musical); powerful organ reed stop

n. tuba, large brass wind instrument having valves and producing tones in the low range; powerful organ reed stop; ancient Roman trumpet (Musical)