τετράεδρος

ον, Subst., τό
A. having four faces, πυραμίδες Iamb. in Nic. p.93 P.: Subst. ‐εδρον,τό, Hero *Deff. 99, Papp. 352.12, Theol.Ar. 24.
Liddell, Scott & Jones
A Greek-English Lexicon, 1940
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