icosahedron /ˌʌɪkɒsəˈhiːdr(ə)n 
, ʌɪˌkɒsəˈhiːdr(ə)n / ▸ noun (plural icosahedra /ˌʌɪkɒsəˈhiːdrə/) (plural or icosahedrons)
a solid figure with twenty plane faces, especially equilateral triangular ones. – ORIGIN late 16th century: via late Latin from Greek eikosaedron, neuter (used as a noun) of eikosaedros ‘twenty-faced’.
EnglishOxford Dictionary of English
