a room in which there is a bath/ bathtub , a washbasin and often a toilet
Go and wash your hands in the bathroom.
a room in which there is a toilet, a sink and sometimes a bath/ bathtub or shower
I have to go to the bathroom (= use the toilet) .
Where's the bathroom? (= for example in a restaurant)
In BrE , but not in NAmE , the room that has a toilet in it is usually referred to as a toilet . This room in people’s houses can also be called the lavatory , or informally, the loo . An extra downstairs toilet in a house can be called the cloakroom . In public places, especially on signs, the words toilets , Gents (for men’s toilets) or Ladies (for women’s toilets) are used for a room or small building containing several toilets. You might also see WC or Public Conveniences on some signs.
在北美英语中，厕所一般称为bathroom，从不叫toilet。公共厕所亦可称为restroom、ladies' room、women's room或men's room，还可用washroom，尤其是在加拿大。
In NAmE the room that contains a toilet is usually called the bathroom , never the toilet . A room with a toilet in a public place can also be called a restroom , ladies’ room , women’s room or men’s room . Washroom is also used, especially in Canada.