n., pl., -ceps·es (-sĕp'sĭz), also triceps.
A large three-headed muscle running along the back of the upper arm and serving to extend the forearm.
[From Latin, three-headed : tri-, tri- + caput, head.]
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.