[ te-truh-hee-druh n ]
/ ˌtɛ trəˈhi drən /

noun, plural tet·ra·he·drons, tet·ra·he·dra [te-truh-hee-druh] /ˌtɛ trəˈhi drə/.

Geometry. a solid contained by four plane faces; a triangular pyramid.
any of various objects resembling a tetrahedron in the distribution of its faces or apexes.

Origin of tetrahedron

1560–70; tetra- + -hedron, modeled on Late Greek tetráedron, noun use of neuter of tetráedros four-sided
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for tetrahedra

  • The atoms are arranged in two tetrahedra with a common apex, and the relationship is maintained in the meta-body, a septet.

    Occult Chemistry|Annie Besant and Charles W. Leadbeater
  • The globe, e, is a new form, the four tetrahedra of the proto level making a single twelve-atomed one on the meta.

    Occult Chemistry|Annie Besant and Charles W. Leadbeater
  • The smallest particles of fire are tetrahedra, of air octahedra, of water icosahedra.

British Dictionary definitions for tetrahedra

/ (ˌtɛtrəˈhiːdrən) /

noun plural -drons or -dra (-drə)

a solid figure having four plane faces. A regular tetrahedron has faces that are equilateral trianglesSee also polyhedron
any object shaped like a tetrahedron

Derived forms of tetrahedron

tetrahedral, adjectivetetrahedrally, adverb

Word Origin for tetrahedron

C16: from New Latin, from Late Greek tetraedron; see tetra-, -hedron
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for tetrahedra

[ tĕt′rə-hēdrən ]

Plural tetrahedrons tetrahedra

A polyhedron having four faces.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.