Turn to move
Turn refers to whose move it is, as in any two-player board game.
In Japanese, 手番 (teban) or just 番 (ban). Also used in the compounds 黒番 (kuroban) and 白番 (shiroban), meaning black's move and white's move, respectively--these are often seen in problem books; see basic Japanese for reading go books.
In Chinese, the term 先 (xian1) means first. So 黑先 (hei1 xian1) and 白先 (bai2 xian1) means black first (to move) and white first (to move) respectively.
An unrelated meaning is the turn shape or play.