belemnite
/ˈbeləmnaɪt/noun
1- an extinct cephalopod mollusc with a bullet-shaped internal shell that is typically found as a fossil in marine deposits of the Jurassic and Cretaceous periods箭石（有子弹形内壳的头足类软体动物, 已绝种, 其化石多见于侏罗纪和白垩纪时期的海洋沉积中）。
1.1
- Order Belemnoidea, class Cephalopoda: many genera.箭石目, 头足纲：多属。
词源
early 17th cent.: from modern Latin belemnites, based on Greek belemnon 'dart'.