tetrahedron
noun /ˌtetrəˈhiːdrən/
/ˌtetrəˈhiːdrən/
(geometry- enlarge imagea solid shape with four flat sides that are triangles
四面体 Topics Colours and Shapesc2词源late 16th cent.: from late Greek tetraedron, neuter (used as a noun) of tetraedros ‘four-sided’.