Hold

A “hold” means an employer has the right to book you first before you take a job anywhere else. If you get “challenged” by another company to book you for the same time, you have to go to the company “holding” you and ask them to decide. They have 24 hours to decide if they want to turn their “hold” into an official “booking” (which means they are obligated to hire/pay you). If they can’t book you, they’ll “release” you, and you’ll become “booked” at the other company. Here's a great resource on how this works.