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.