:a stick with a weight at the bottom that swings back and forth inside a clock钟摆;摆锤 — often used figuratively常用作比喻
The fashion pendulum swung from silver jewelry to gold and back again. [=silver jewelry was popular for a while, then gold became popular, and then silver became popular again]流行时尚从银饰变换到金饰,又从金饰变换回银饰。