pendulum
n.
1660, from Modern Latin pendulum (1643), noun use of neuter of Latin adjective pendulus "hanging down," from pendere "to hang" (see pendant). The Modern Latin word is perhaps a Latinization of Italian pendolo.
〔李〕[pend=to hang挂；-ulum (-um) n.=thing物→“thing that hangs悬挂着的东西”→] n. thing hanging from a fixed point so as to swing freely, as in a clock悬摆；钟摆