A Grip is a term that dates back to the early days of the Circus. It carried on from there to Vaudeville and on to todays music and film soundstages. These are the people that do the laborous work on these sets. They push, pull, roll, and lift various peices of equipment under the watchful eye of the director, Producer, or art director etc...

"He's got a good Grip!" (set of hands)