n.pl. tra·pe·zi·ums or tra·pe·zi·a(-ze-ə)
a. A quadrilateral having no parallel sides.
b. Chiefly British A trapezoid.
2. Anatomy A bone in the wrist at the base of the thumb.
[Originally, a quadrilateral with two parallel sides (later confused withTRAPEZOID, originally, a quadrilateral having no parallel sides), fromModern Latintrapezium, a quadrilateral with two parallel sides, fromLate Greektrapezion, fromGreek, diminutive oftrapeza, table : tra-, four; see kwetwer- in the Appendix of Indo-European roots + peza, foot; see ped- in the Appendix of Indo-European roots.]
(click for a larger image)trapezium
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.
American Heritage Dictionary Products
The American Heritage Dictionary, 5th Edition
The American Heritage Dictionary of Idioms
The American Heritage Roget's Thesaurus
Curious George's Dictionary
The American Heritage Children's Dictionary
The American Heritage Dictionary of Indo-European Roots
The American Heritage Student Grammar Dictionary
The American Heritage Desk Dictionary + Thesaurus
The American Heritage Science Dictionary
The American Heritage Dictionary of Business Terms
The American Heritage Student Dictionary
The American Heritage Essential Student Thesaurus