How limited are we for space? If it needs to be that short, something along the lines ofImperial wrote:... what would you guy's suggest to be written about the euph in such a brief form?
"euphonium = brass instrument, tenor member of the tuba family"
might work. If more space is available, you might add
"similar in size and appearance to a baritone horn, but with a more mellow sound".
I'm sure there are other things that could be said (given the room), and probably better ways of wording what I've written above.
Best of luck!
