bathroom

A room containing a shower or bathtub, and (typically but not necessarily) a toilet.

“down this ‘ere little stair–mind your ‘ead, mum–everythink is modern, put in by Mr. Noakes w’en ‘e took to lettin’ for the summer.” ”A bathroom?” asked Harriet hopefully. ”Well, no, m’lady, not a bath'''room,” replied Mrs. Ruddle, as though that were too much to expect, “but everythink else is quite modern as you’ll find–only requirin’ to be pumped up night and morning in the scullery.”

Although there was a cloakroom on the ground floor, the Old Rectory had only one bathroom, a defect which necessitated embarrassed, low-voiced enquiries before anyone upset their carefully worked-out rota by taking an unexpected bath.

A lavatory: a room containing a toilet and (typically but not necessarily) a bathtub.

Most Americans don't know 'WC' and many Brits mock 'bathroom' but almost everyone understands 'toilet' or 'lavatory'.

To assist a patient with using the toilet and general personal hygiene.