Upright curves

= parenthesis, round brackets
круглая скобка, простая скобка; мн. круглые скобки, простые скобки
♦ Either or both of the upright curved lines, (), used to mark off explanatory or qualifying remarks in writing or printing or enclose a sum, product, or other expression considered or treated as a collective entity in a mathematical operation.

— Игорь Мостицкий (обсуждение) 16:07, 9 января 2026 (MSK)