1. In sports or another competition, to lose (or, of a pitcher in baseball or softball, to be credited for a loss). In a box score, a loss is recorded as "L." Which pitcher took the L last night? The home team took the L after losing a huge lead.

2. By extension, to accept failure in some endeavor or pursuit. They rejected the ad campaign I created, so I'm going to have to just take the L and move on.