In restaurants, airports, museums and other commercial entities, the signs say "Restrooms". Once you get there, there can be different names for the individual doors. Ladies/Women and Men are the most common. If it's a themed restaurant, you get Wahine & Kane (Hawaiian),Damen & Herren (German theme), Senioritas & Caballeros (Mexican in the west) or little diagrams, round for women, triangle for men, or pictures of a figure in a skirt and one with pants.
Artemis - an expert on the "facilities"
P.S. I first learned "thunder mug" while in Minnesota in a farm house with only an outside privy and it was raining so hard you didn't dare go out to dash to it.
