I've heard a few musicians say "man I was comping for this guy the other night" or " I was so glad when I could finally comp her licks".

I just acted like I knew what they were talking about

But I've heard the term used in what seems two different ways. One meaning seems to mean playing rhythm for someone else who's playing lead or melody over and the other meaning was used like in copying someone elses riff/licks/phrase...

How do you use the term? What's it mean to you? Thanks