Jessica Noyes Mar 31, 2012:

Sports? My first thought was that this is some kind of sports analogy -- like half-time, then third quarter, etc -- a sports analogy carried over into the world of education. There are several sports-related hits for this term on Google; this is only one of them: http://blogs.mercurynews.com/buzz/2007/09/16/49ers-mid-third... ... So I am wondering if Spanish has a term that could relate to either sports or school, rather than those suggested below that are purely academic. Knowing a little more about the context would of course be helpful here.