u·re·thra (yo?o-r??thr?)n. pl. u·re·thras or u·re·thrae (-thr?) The canal through which urine is discharged from the bladder in most mammals and through which semen is discharged in the male.[Late Latin ?r?thra, from Greek our?thra, from ourein, to urinate.]u·re?thral adj.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.urethra (j??ri??r?) n, pl -thrae (-?ri?) or -thras (Anatomy) the canal that in most mammals conveys urine from the bladder out of the body. In human males it also conveys semen[C17: via Late Latin from Greek our?thra, from ourein to urinate] u?rethral adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014u?re?thra (y??ri ?r?) n., pl. -thrae (-thr?), -thras. a duct that conveys urine from the bladder to the exterior and, in most male mammals, also conveys semen. [1625?35;