In this case it was a bike and a run back-to-back. In general, it can be any 2 workouts back-to-back. But generally, it means a bike then run. You use it to practice transitions, as well as helping the legs learn going from biking form to running form as it can be a weird transition for people.

I did my first brick workout for a triathlon I'm training for! That was cool.

I'd like to! Most of the more niche places I go to aren't here yet and that's hard for me.