Humourous term for the restroom (or "WC" in Europe). It gives the user an air of vain intelligence and sophistication to apparently use a Latin term when, in reality, the user is probably too stupid to even know Pig Latin. See also "Leakatorium" and "poopalorium"
Damn, that quart of beer went right through me. Gentlemen, pleaseexcuse me. Frank, where's your pissalorium?
When a men's restroom
Consists mostly of urinals, or when the men in said restroom are mostly pissing. One such example would be at a sporting event where men are in line to use the urinal.
John: "I went into the restroom and there was piss all over the seats, and everyone was waiting in line!"
Mike: "Sounds more like a pissitorium to me."