1 a chain or stick with a heavy weight at the bottom that moves regularly from side to side to work a clock 摆；摆锤；钟摆

2 a way of describing a situation that changes from one thing to its opposite （局面）摇摆不定: Since last year's election, the pendulum of public opinion has swung against the government. 自去年的选举以来，舆论转向反对政府。