Buy-In
A chunk of work you complete before the main body of the workout starts.
What it means in a class
A buy-in is work you have to finish before you begin the main workout — typically a run, a row or a set number of reps. It's a way of adding a fixed cost to the front of a session.
The mirror image is the cash-out at the end.
On the whiteboard
Buy-in: 800m run, then 3 rounds of the AMRAP.