an egg with a double yolk; a double (binary) star; double doors; dual controls for pilot and copilot; duple (or double) time consists of two (or a multiple of two) beats to a measure.

• 双黄蛋；双星；双重门；驾驶员和副驾驶员的双重控制；两拍是由打两下节拍组成的。