< /aɪˌkoʊ səˈhi drə, aɪˌkɒs ə-/.
- a solid figure having 20 faces.
noun plural -drons or -dra (-drə)
- a solid figure having 20 faces. The faces of a regular icosahedron are equilateral triangles
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).
Plural icosahedrons icosahedra
- A polyhedron having twenty faces.