Just a question

What is a grip? What is a key grip? I have seen this so many times in credits and I have no idea what it means.

Cheers, pix

In American and Canadian film-making, the key grip is the chief grip (lighting and rigging technician) on the set. Like a foreman, the key grip directs a crew of grips, some with specialized skills such as dolly grips, crane operators, camera car operators, etc. The key grip is sometimes credited as the first company grip.

Yes I copied that from wikipedia. You could too.