This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

n. Plural form of tetrahedron.

"Lowell Gilbert @ 13, kid bitzer @ 15 -- Remember that the tetrahedral shape is that of the four bonds of the carbon atom; the implied tetrahedra are connected tip-to-tip, not solidly packed."

bond-equivalent    polyhedra    matchstick    lance-head    glockenspiel