1) To urinate. Not now in polite use but frequent formerly.
1519 the hangynges of the where [choir] lyeth opynly in the presbitory, dogges pysses of thame, wax droppys of thame, York
1544 the place of Owsbrige callyd the pyssing howes, York
1677 Hall tooke his hatt from him and pissed in it, Barnsley. Its use as a name for a boundary marker may suggest that this was where the walkers traditionally relieved themselves: 1707 and so goeth North to a place called Pissinghow, Brompton.