IPA: //ˌrɒm.bəʊˈhɛd.rən//
KK: /ˈrɑːmboʊˌhɛdron/
A three-dimensional shape that has six flat surfaces, all of which are rhombuses.
The architect designed a building in the shape of a rhombohedron to create a unique look.
Rhombohedron → It is formed from "rhombo-" (from Greek "rhomboides", meaning rhombus or parallelogram) and "hedron" (from Greek "hedra", meaning face or base). The word describes a three-dimensional shape with faces that are rhombuses.
Imagine a shape with faces that look like rhombuses — that's what a rhombohedron is, combining the idea of a rhombus ('rhombo-') and a face ('hedron').
No commonly confused words.