He played a bit of flute (and for a brief stint, tuba) in the high school band with just a rudimentary sense of the instruments. In its place is a moist warmth, heavy with the scent of heliotrope and tuba roses. On the boards below was spread a banquet of rice and tuba for the multitude.
http://www.dictionary.com/browse/tuba
British Dictionary definitions for tuba Expand. /ˈtjuːbə/. noun (pl) -bas, -bae (-biː) 1. a valved brass instrument of bass pitch, in which the bell points upwards and the mouthpiece projects at right angles. The tube is of conical bore and the mouthpiece cup-shaped.
http://www.dictionary.com/browse/tuba
The lowest-pitched of the brass instruments. In orchestras, the tuba is usually held across the player's lap. In marching bands, the sousaphone is generally used as a low brass instrument because it was designed to be carried.
http://www.dictionary.com/browse/tuba
Tubas come in a number of keys: BB flat, CC, E flat, F, and GG, though the tuba is what is called a non-transposing instrument, as its music is read and played in concert pitch. There are many design configurations for the tuba.
http://www.blackdiamondbrass.com/tbahist/tubahist.htm
The euphonium and the baritone differ in that the bore size of the baritone horn is typically smaller than that of the euphonium, and the baritone is primarily cylindrical bore, whereas the euphonium is predominantly conical bore.
https://en.wikipedia.org/wiki/Euphonium
The tuba is an instrument for which there was a demand long before its creation. Various inventors sought to fill the desire of composers, bandmasters and orchestra conductors for an instrument that could supply the bottom end, especially in the days when orchestras were growing exponentially in size.
http://www.blackdiamondbrass.com/tbahist/tubahist.htm
Though this researcher can never hope to do justice to this instrument in so short a piece, it nevertheless is my hope that this overview will provide the basis from which to form meaningful direction and questions in the minds of those who wish to know more about this instrument, its origins and related instruments.
http://www.blackdiamondbrass.com/tbahist/tubahist.htm
A person who plays the euphonium is sometimes called a euphoniumist, euphophonist, or a euphonist, while British players often colloquially refer to themselves as euphists, or euphologists. Similarly, the instrument itself is often referred to as eupho or euph.
https://en.wikipedia.org/wiki/Euphonium
Though the tuba has a conical bore, its profile is not that of the bass Saxhorns, which are members of the cornet  pistons (cornopean) or valved bugle family. The tuba has a wider conical bore profile and deeper cup mouthpiece.
http://www.blackdiamondbrass.com/tbahist/tubahist.htm
The euphonium is a large, conical-bore, baritone-voiced brass instrument that derives its name from the Greek word euphonos, meaning well-sounding or sweet-voiced (eu means well or good and phonos means of sound, hence of good sound).
https://en.wikipedia.org/wiki/Euphonium
what is a tuba
The tuba is a valved brass instrument of brass pitch, in which the bell points upwards and the mouthpiece projects at right angles. A tuba is a valved brass instrument of bass pitch, in which the bell points upwards and the mouthpiece projects at right angles.