Any of these words will get you directed to the necessary place if you ask "Where's the X?" in a restaurant anywhere in the world. However, the meaning is not always the same for all native speakers, particularly for British and American English speakers. They all have one or more of the following basic meanings. 1. An object: a receptacle which we use to relieve ourselves of bodily waste. 2. A room containing #1 (usually with some handwashing facilities) 3. A room containing a bathtub and usually a washbasin, shower and probably (but not necessarily) #1. Now let's look at how the words are (or aren't) used by American and British English speakers: American English: Toilet: Only #1 This is why you should not say "Where is the toilet?" or "I'm going to the toilet" in AmE contexts. It seems quite direct and vulgar. When an AmE speaker hears the word 'toilet', they think of the actual toilet bowl, so it doesn't sound very polite. Bathroom: #2 and #3 For the reason above, AmE users tend use the word 'bathroom' in most polite situations. If an AmE speaker asks where the 'bathroom' is, they're probably asking to be directed to a room containing a toilet and washbasin. Can be in a public place or private home. Restroom: #2 Used in the same way as 'bathroom' (meaning #2) above, but used more for public places. WC: not used Loo: not used British English Toilet: #1 and #2 This is why it's OK to say "Where's the toilet?' in BrE - it's the room as well as the object. It's a little bit direct, but quite acceptable. Bathroom: only #3 A BrE speaker would only usually use a 'bathroom' to take a bath or shower. Restroom: not used WC: #1 and #2 Rare. Very outdated and never used in conversation. You may occasionally see it written on signs and doors. Loo: #1 and #2 Typically British and very widely used. It's a friendly, polite and informal alternative to 'toilet'.

They are all the same thing. Bathroom and restroom are used in the US and toilet and loo are used in the UK. WC or "water closet" is old fashioned but it is sometimes used in the UK.

Thank you

Just to add - Canadians use the word "washroom" the way that Americans use "restroom."

"toilet", "WC" and "loo" all refer to the same thing. A "bathroom" can refer to a toilet, but sometimes it has nothing to do with a 'toilet'. It can be simply a room with a shower/bath/wash basin. It may have a toilet or it may not. A restroom usually refers to a toilet facility, but not all the time. Sometimes it is just a room designed for people to relax in. I've seen restrooms in my country that are simply to lounge about in. Comfortable chairs, etc.