Jakes 3

My father used to use this word (along with a few others less appropriate to polite company)

As far as I can tell it has origins in Irish and British slang, and I've seen it used in some writings from the 1880's and '90's.

Since there is a decent bar in my town, called Jake's Place, which actually has a guy called Jake behind the stick, I've always been tempted to walk into Jake's and ask Jake if I can use the Jakes.