the picture says basin but according to Oxford dictionary that is not correct.

That is a basin. What Oxford dictionary?

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We need a Briton. What I call a sink they call a basin. But the definitions you link to also permit your plastic tub to be called a basin in both countries. "a wide open container used for preparing food or for holding liquid" or "a large round bowl for holding liquids".
I'd call that a plastic bowl.
Grammar GeekI'd call that a plastic bowl.
Yeah, I assumed it was pretty big since he is doing laundry in it. How big does a bowl have to be before it becomes a tub? Or a basin. For me, a basin is what you get with a ewer to wash up in your Victorian hotel room.
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so to sum up, the plastic thing that you wash your clothes in is called basin (more British English) or Tub (More American English) ?
American answer: I call something like that for washing clothes in a washtub. A tub is a bathtub, all else being equal. Tubs are usually not round. A basin or washbasin is a wide, round, flattish bowl for washing your face in. A receptacle for water attached to a supply and a drain is a sink.
I didn't see the part about doing your laundry in it. I'd go with plastic basin or plastic wash basin or small plastic tub or a small plastic washtub. I do feel (as enoon said) that usually a basin is flattish and not deep, but if you said you were doing your laundry in it, I'd adjust my mental image.

I'm still thinking that "We had to do our laundry in this honking big plastic bowl" is not out of the question.
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