Katsu definitions

(Zen Buddhism): A word shouted out in Zen Buddhism, (as well as other sects of Buddhism), and in East Asian martial arts schools, used to help focus one's energy, (気 (き, ki), and therefore induce an enlightened state of oneself or another. It is stemming from this that it is also often inferred to be a verbal punishment.

Origin of katsu

From Japanese 喝 (かつ, katsu).