It's pretty common to call all wind instruments horns in a band context, it is a trumpet but most musicians aren't going to be mad at calling it a horn. Still a bad pick up line
Trumpeter here, I'd be insulted if I was called a horn. Might be regional, but that's not common here. If we're speaking about horns, it's only French horns
In horns, unlike some other brass instruments such as the trumpet, the bore gradually increases in width through most of its length—that is to say, it is conical rather than cylindrical.[1]
Which seems to specifically exclude trumpets from horns.
In my experience its very common, just to give a counterpoint. "Bring in the horns" to denote a trumpet heavy section, or just referring to the brass section as "the horn section". 8dk might just be reguonal i guess but its colloquial.
Differently, because that's a poor analogy. Trumpets are horns, guitars are stringed instruments. Now, if they called their trumpet a kazoo, it'd be time to throw down.