I learned that トイレ is loaned from the English word "toilet".
However, in the US, toilet usually refers to the thing that you sit on when you poop. And in the UK, toilet usually refers to the whole place where you wash your hands and poop.
Hopefully you know what I mean...
So which of the above does トイレ refer to?
When a word is loaned by another language, it is not always true that a loan word has the exact same meaning as the original word. You have to know how it is used in Japanese to know what it means in Japanese.
トイレ has both meanings. For example:
トイレに[行]{い}ってもいいですか? (Literally) Is it OK to go to the bathroom (restroom)?
トイレが[流]{なが}れません. The toilet doesn't flush.
It doesn't matter what the word toilet means in English. What matters more is what トイレ means in Japanese as it is a Japanese word.
As @DavidRicherby commented, the word toilet generally means
In British English: both the room and the sanitary fixture.
In American English: Only the sanitary fixture and not the room.
Both, or I would rather say, there's no distinction. トイレ just means "the place you use for excretion", where what the "place" exactly refers to is undesignated.
For example:
二階には男子トイレしかない。 → the room = お手洗い, 化粧室 etc.
三番目のトイレには幽霊が出る。 → the stall = 個室
トイレに紙がつまった。 → the stool = 便器
All of above are valid.
As you say, Japanese word, トイレ is a loaned word from English, toilet, which according to Concise Oxford English Dictionary (10th Edition) means “a large bowl for urinating or defecating into, typically plumed into a sewage system. But トイレ is equivalent to original Japanese word, 便所 which means a room containing a toilet or toilets. We call “a large bowl for urinating or defecating into, a 便器.
Although we have 便所、お手洗い、洗面所、化粧室 as its alternatives, it’s lucky that we Japanese can do with ”トイレ” for complex mix of English “Washroom”, “restroom”, “bathroom”, “lavatory”, "privy," “toilet,” “toilet room,” "the gents", "Saint john’s," "john", or "jack" as shown in the following question posted in SE English language & Usage site:
“Washroom”, “restroom”, “bathroom”, “lavatory”, “toilet” or “toilet room”
I've always been confused by the terms washroom, restroom, bathroom, lavatory, toilet and toilet room. My impression is that Canadians would rather say washroom while Americans would probably say bathroom or Saint John's in the same situation. Which do you usually use? Please specify the difference if you use more than two from those six with different meanings, and also where you are from. - https://english.stackexchange.com/questions/8281/washroom-restroom-bathroom-lavatory-toilet-or-toilet-room?newsletter=1&nlcode=15318%7ce1f1
トイレ refers to the bathroom.
The toilet seat is called 便座 or 便器.
トイレ means restroom, so nearly meaning of toilet in UK.
