duct through which urine is discharged in most mammals and which serves as the male genital duct
百科解释
In anatomy, the urethra (from Greek ο?ρ?θρα - ourethra) is a tube that connects the urinary bladder to the genitals for the removal of fluids from the body. In males, the urethra travels through the penis, and carries semen as well as urine.