What Is Considered A Calico Cat?

By my understanding of the term - yes.  In UK we call cats with black, brown and cream splodges "tortoiseshell".  If they also have white on them, then they are "tortoiseshell and white".  I understand that the USA calls this colour pattern "calico".  The proportion of the cat showing each colour can vary enormously, but for show cats they like the colours to be as evenly represented as possible.  
Worth noting - this pattern is sex-linked, and most are female.  Males in this colour have a genetic abnormality and are almost always sterile.

A calico cat has orange, white, and black.