the use of 万葉仮名 (man'yōgana) to spell sounds in Old Japanese, irrespective of the kanji's meaning

high treason

(historical) Chang'an

plank, board / (cooking) Short for 俎板. / (cooking) Short for 板前. / (cooking) Short for 板場. / (laundry) Short for 洗濯板. / (Internet) board (sub-unit of a larger BBS or imageboard)