[sef-uh-loh-thawr-aks, -thohr-]

noun, plural ceph·a·lo·tho·rax·es, ceph·a·lo·tho·ra·ces [sef-uh-loh-thawr-uh-seez, -thohr-] /ˌsɛf ə loʊˈθɔr əˌsiz, -ˈθoʊr-/. Zoology.

the anterior part of the body in certain arachnids and crustaceans, consisting of the coalesced head and thorax.

Origin of cephalothorax

First recorded in 1825–35; cephalo- + thorax
Related formsceph·a·lo·tho·rac·ic [sef-uh-loh-thuh-ras-ik] /ˌsɛf ə loʊ θəˈræs ɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

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Historical Examples of cephalothorax

British Dictionary definitions for cephalothorax


noun plural -raxes or -races (-rəˌsiːz)

the anterior part of many crustaceans and some other arthropods consisting of a united head and thorax
Derived Formscephalothoracic (ˌsɛfələʊθəˈræsɪk), adjective
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

Word Origin and History for cephalothorax

1829, from cephalo- + thorax. Perhaps from French or German.

Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for cephalothorax



The combined head and thorax of arachnids, such as spiders, and of many crustaceans, such as crabs.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.