> Well, "half bathroom" would sound silly over here. Either the room has a
> bath or it hasn't! If the latter is the case then it ain't a bathroom :)
>
> I guess "half bathroom" might be understood, if it were understood at
> all, to mean that it had a shower rather than a proper bath tub.
From what I understand, a half-bath is just a toilet and sink. A full bath has a
shower/tub. I think this derives mostly from the use of "bathroom" as a
euphemism for "toilet room".
> Why do realtors/estate agents need to use such unintuitive euphemisms for this
> very necessary little room?
For the same reason lawyers and doctors use unintuitive Latin phrases for their
very necessary (okay, arguably necessary in the case of lawyers) little
procedures and things. Every field has its jargon--compare the meaning of
"work" when used by a physicist as opposed to by a construction worker. :)