In message , at 09:03:55 on Fri, 7 Jan
2011, Miles Bader remarked:

I hadn't come across these niceties of 'full' and 'half' baths.

I've only seen those used in real-estate advertisements, presumably to
avoid using a "low" word like toilet (which is what a "half bath" is...).

In US-English a WC is also called a bathroom (especially in public
places like shops and restaurants). So in a house you do need to be able
to distinguish between 'full' and 'half'. It also allows a more compact
advert because you can simply say (eg) "2.5 bathrooms".

In the UK the half-bath is normally called a "cloakroom" in real-estate
speak. Ironically, many in older houses really are a conversion of a
room off the entrance hall for storing coats; which I suppose they'd
have to describe as a "coat cupboard".
--
Roland Perry