In the good old days, in the UK sanitaryware industry, sanitary pottery casters and warehouse packers, called a WASHBASIN a TABLE. But why?
Well, in the late 1800s when large WASHBASINS were designed to stand on legs rather than a single column pedestal (as is common in the UK today, 2015) the washbasin actually looked like a TABLE.
Simples. But actually, the correct word, in those days, for a WASHBASIN or TABLE was LAVATORY.
The word LAVATORY is derived from the Latin word LAVARE, meaning 'to wash.'
Nowadays, a TOILET is often mistakenly called a LAVATORY since this is regarded as polite. But technically, it is incorrect.
Of course, while it would be correct to wash your hands in a LAVATORY or WASHBASIN or SINK (see below) it would be odd to wash your hands in a TOILET, or worse still, to do something 'exceptional' in a LAVATORY, WASHBASIN or SINK, don't you think?
And then there is the case of a SINK. This is not a WASHBASIN or a LAVATORY (or for that matter a TOILET) but a sink is designed for 'robust' use, perhaps in a kitchen. And it doubles up as a LAVATORY or WASHBASIN when you need to wash your hands, which is the end part (the grasping organ) of a person's arm beyond the wrist, including the palm, fingers, and thumb.
At Twyfords a standard sized SINK was called a JOMUK. And sink designs do vary. More here>
Told you it was messy, complicated and a tad confusing!