弹壳

ammunition case

crossball / bullet / shot / shell / ball

to pluck (a string) / to play (a string instrument) / to spring or leap / to shoot (e.g. with a catapult) / (of cotton) to fluff or tease / to flick / to flip / to accuse / to impeach / elastic (of materials)

shell / carapace / crust (earth's crust etc) / also pr. [ke2]