urea

n [U] white soluble crystalline compound contained esp in the urine of mammals 尿素.

uptown, upturn, upturned, upward, upward (also upwards / -wEdz; -wLdz/), upward mobility, upward(s), upwards, upwards of, upwind, uranium, urban, urbane, urbanely, urbanity, urbanization, urbanisation, urbanize, urbanize, urbanise, urchin, Urdu, ureter, urethra, urge, urge sb to do, urge sb. on, urged, urgency, urgent, urgently, uric, urinal, urinary, urinate, urine, urn, us, USA, usable, USAF, usage,