(typography) the iteration mark 〻, used to repeat kanji, historically mostly kanji with kun'yomi

(inorganic chemistry) nitrogen dioxide

double negative

double room

going back to sleep (e.g. after waking up in the morning)

twelfth day of the month

Used other than figuratively or idiomatically: see 二, 枚, 目. (the second sheet or other flat thing) / a handsome male character, especially one that gets involved in a romance during the story

(electronics) diode (rectifier tube)

(grammar) Short for 下二段活用 (shimo nidan katsuyō): lower bigrade conjugation

twelve o'clock; noon; midnight