record (a song or piece of music) to demonstrate the capabilities of a musical group or performer or as preparation for a full recording

they've already demoed twelve new songs

demonstrate the capabilities of (software or another product)

Apple is expected to demo the newest version of its mobile operating system at the conference next week

a demonstration of a product or technique

a cookery demo

a public meeting or march protesting against something or expressing views on a political issue

a peace demo

both channels managed to maintain ratings among young male demos