The American Heritage® Dictionary of the English Language, 4th Edition
n. A long, narrow, convoluted tube, part of the spermatic duct system, that lies on the posterior aspect of each testicle, connecting it to the vas deferens.
n. A narrow, tightly-coiled tube connecting the efferent ducts from the rear of each testicle to its vas deferens, where sperm are stored during maturation.
the GNU version of the Collaborative International Dictionary of English
n. An oblong vermiform mass on the dorsal side of the testicle, composed of numerous convolutions of the excretory duct of that organ.
The Century Dictionary and Cyclopedia
n. An elongated oblong body resting upon and alongside the testicle, mostly enveloped in the tunica vaginalis.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a convoluted tubule in each testis; carries sperm to vas deferens
Word Usage
"The epididymis is a very tiny, tightly coiled tubule, which runs along the back of the testicle from top to bottom."