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n. pl. tris·oc·ta·he·drons or tris·oc·ta·he·dra (-drə)
A solid figure having 24 equal faces, every three of which correspond to one face of an octahedron.

[Greek tris, thrice; see trei- in Indo-European roots + octahedron.]

tris·oc′ta·he′dral (-drəl) adj.


n, pl -drons or -dra (-drə)
(Mathematics) a solid figure having 24 identical triangular faces, groups of three faces being formed on an underlying octahedron
[C19: from Greek tris three times + octahedron]
trisˌoctaˈhedral adj


(trɪsˌɒk təˈhi drən)

n., pl. -drons, -dra (-drə).
a solid bounded by 24 identical faces in groups of three, each group corresponding to one face of an octahedron.
[1840–50; < Greek trís thrice + octahedron]
tris•oc`ta•he′dral, adj.
References in periodicals archive ?
A few topazolite crystals recovered in December 2009 are modified by the trisoctahedron {332} and tetrahexahedron {210}.
Forms present are the cube (a), octahedron (o), dodecahedron (d), tetrahexahedron (e) {012}, trapezohedron (m) {113}, trisoctahedron (q) {133}, and hexoctahedron (t) {124}.
The easy-to-identify species were glass-clear analcimes with cube, (211) trapezohedron, and {332} trisoctahedron faces; large for the species, transparent, very sharp, almost single crystals of gobbinsite; molybdenite; donnayite; pyrochlore; and tetranatrolite.