present participle of back up

(Construction) A compressible material placed in a joint before applying sealant.

present participle of back off

present participle of back out

A prerecorded piece of music used to accompany a musician who sings live

present participle of back down

present participle of back water

present participle of piggy-back

Support, especially financial. / A liner or other material added behind or underneath. / (television, film) A backdrop. / (music) Musicians and vocalists who support the main performer.

(music) Providing support for the main performer.