A toilet is a large bowl with a seat, or a platform with a hole, which is connected to a water system and which you use when you want to get rid of urine or faeces from your body.

A toilet is a room in a house or public building that contains a toilet.

You can say that someone goes to the toilet to mean that they get rid of waste substances from their body, especially when you want to avoid using words that you think may offend people.