A stabilizer is a tool for keeping a video camera steady, reducing or counteracting movements caused by shaky hands, thereby "stabilizing" the captured footage.
Stabilizers can be physical devices that attach to a camera, like a gimbal or tripod. They may also be a software tool like the Warp Stabilizer found in Adobe Premiere Pro, which is used on digital video footage. Software stabilizers usually crop the edges of the footage. This adjustment creates the necessary space to rotate the video in the opposite direction of the movement.