A term that sounds like it should be related is best boy. No, this is not the ring bearer at the wedding.
You have probably seen the term best boy if you stated after a movie to see the credits scroll by on the big screen.
There is a bit of differences in some of the definitions I read. Here is what I can tell:
A best boy’s job is to assist the person in charge of fitting or repairing the electrical equipment – usually during the filming of a movie.
Another definition called the best boy the principal assistant to the gaffer or grip on a film crew
So, that leads one to say, what is a gaffer? As best I can tell, a gaffer is the chief electrician on a motion picture or television production. In the theater, it may be a stagehand, especially one working on the stage floor.
A grip or key grip on the other hand, is a term used in movies and television. The key grip is the general assistant who is available for shifting scenery, moving furniture, etc.