A calico cat has distinct patches of black, orange/ginger and white. The colors should not run together. The coloration is the result of a genetic quirk, and almost always occurs in female cats. Male calicos are exceedingly rare, and when they do occur they are usually sterile. As far as I know, they are called calico cats on both sides of the Atlantic. Though, in the UK the term tortoise may (I'm not sure) also be applied to calicos.

My current calico cat is very pretty, but obviously chose beauty over brains. She was totally unphased by my acquisition of a new Rottweiler -- she clearly thought it was the old one who had died six months previously. She also growls at thunderstorms to make them go away (they do...eventually), and keeps the dust bunnies under our bed safe from maurading guests.

Hope this helps...and good luck with your song.