A city in Scotland is a city because it has a Royal Charter. Having a cathedral
or university does not make a town a city. In England a cathedral may be
sufficient, I'm not sure. In the US, I believe it's simply by population. The OED
gives a definition of city which they claim is UK wide but I feel is wrong
regarding Scotland. After an extensive debate on this in August 1999 under the
topic "Dunfermerline - city status?" on soc.culture.scottish (find it on
http://www.deja.com/), I wrote to the OED regarding this and the term
"High School" which I also felt to be wrong.
Oxford University Press wrote back to me and said:
"I agree with you that the definitions of 'High School' and 'city' may be
misleading in respect to Scotland, and we will consider revising them at the
earliest opportunity."