(verb or noun) A musical figure of speech used especially in jazz performance which refers to the act of playing chords, usually in parallel with a solo melody. Thus comping is done with instruments like a piano or guitar. Good jazz comping is rhythmically interesting, harmonically varied and provides appropriate background to the melody and foreground to the bass line and percussion. Origin unknown; perhaps an abbreviation of compose.

Though I think this could have been done in one writeup, I like the idea.

The origin, it seems to me, is accompanying, or accompaniment.

Of course, not limited to jazz, but any time--in my case--a keyboard, piano, or synthesizer is used to accompany, another instrument or instruments, or a voice.

Even, and especially, when I work up a comp for myself when I sing, say Satin Doll by Duke Ellington, As Tears Go By by the Rolling Stones, or my own stuff.

I'm teaching a young student of mine this now. She has the most large voice, and will be overwhelming when she can do her own comping