Synonym of 亜酸化窒素 (asanka chisso, “nitrous oxide”); dinitrogen monoxide

twenty-first day of the month

number

warehouseman, guard or keeper of a warehouse

Sokoban (a computer puzzle game)

emergency telephone number 110 to call the police in Japan

an official title in the Edo shogunate of assistant guards, who assisted Osaka guards and Sunpu guards in guarding a castle when there was a shortage of people

number three

Short for 番組宣伝 (bangumi senden).

(Internet slang) good digits (5channel post number, Niconico Video video ID number, hit counters, etc.)