[Aqwis]

> This seem to be the reason that in some places people often refer to "catholic" as "roman catholic".

That's not really why, is it -- it's because there are also the Eastern Catholic (as opposed to Eastern Orthodox) churches that recognize the Pope as the leader of the Church while using different rites (including allowing married men to be priests).

[Gupie]

There are also Anglican Catholics that believe basically the same doctrine as Roman Catholics but have the Queen of England as head instead of the Pope.