device, mechanism

secret

secret

room (of a house or hotel), chamber, apartment, flat / (sumo) a stable where rikishi live and train together under a shisho oyakata (stable master)

(cryptography) secret key

secret police

secret base (of the military, of children, etc.)

secret society

an adult son residing with his parents; generally has not yet or can not come into family inheritance / a female servant working in a daimyō, ōoku, or other high-ranking house

room rent