Definition of trombones:
(n) :
A musical instrument in the brass family, having a cylindrical bore, and usually a sliding tube (but sometimes piston valves, and rarely both). Most often refers to the tenor trombone, which is the most common type of trombone and has a fundamental tone of B♭ˌ (contra B♭).
(n) :
The common European bittern.
(n) :
(film, television) A kind of extendable support for attaching lighting elements to a set.
(v) :
(telecommunications) To transmit a signal or data back to a central switching point before sending it out to its destination.
(v) :
(film, slang, transitive) To extend and retract (the zoom lens); to use it too enthusiastically.