main scope tube（主镜筒）是什么意思？音标发音+图解场景

主镜筒 /ˈmeɪn ˈskəʊp ˈtjuːb/ n

English: main scope tube · 主镜筒

释义：Cylindrical body of the telescopic sight that houses the optical system and through which the light travels.

这个词出现在以下图解场景（1）