Allen key; hex head wrench

異種格闘技戦: a combat sport match where opponents compete against each other using different styles of martial arts

(card games) a three of a kind

a wreath

hidden / concealed / secret

a box-shaped receptacle, e.g. a coin bank or letter box (e.g. 銭函, 投函する) / to insert [into a container] (cf. 入れる, 容れる) / a suit of armor (more commonly 鎧)

to polish / study of ... / to sharpen / inkstone / a surname

(computing) computational linguistics

nuclear submarine

computational linguistics