Icosahedron

[ahy-koh-suh-hee-druh n, ahy-kos-uh-] /aɪˌkoʊ səˈhi drən, aɪˌkɒs ə-/

noun, plural icosahedrons, icosahedra
[ahy-koh-suh-hee-druh, ahy-kos-uh-] /aɪˌkoʊ səˈhi drə, aɪˌkɒs ə-/ (Show IPA)
1.
a solid figure having 20 faces.
/ˌaɪkəsəˈhiːdrən/
noun (pl) -drons, -dra (-drə)
1.
a solid figure having 20 faces. The faces of a regular icosahedron are equilateral triangles
n.

1560s, from Greek eikosahedron, neuter of eikosahedros, from eikosi “twenty” + -hedra “seat, base, chair, face of a geometric solid,” from PIE root *sed- (1) “to sit” (see sedentary). Greek eikosi is from PIE *wikmti- “twenty,” from *wi- “in half,” hence “two” + (d)kmti-, from root *dekm- “ten” (see ten).
icosahedron
(ī-kō’sə-hē’drən)

Plural icosahedrons or icosahedra
A polyhedron having twenty faces.

icosahedral adjective