caps Share definition Flag 1. short for Capital letters. 2. the Caps Lock key/what happens when you hold down shift and type. 1. Every Word In This Sentence Begins With A Capital Letter. 2. ARGH I AM NAGRY PH34R MY CAPS!!! caps by TheMouse December 11, 2004 0 0 Get merch Get the caps mug. Buy Now — $32.95 See more merch