Piss \Piss\, v. t. & i. [OE. pissen, F. pisser; akin to It. pisciare, D. & G. pissen, Dan. pisse, Icel. pissa.] To discharge urine, to urinate. --Shak.
Source: Webster's Revised Unabridged Dictionary (1913)
Piss \Piss\, n. Urine.