Calico and Tortoiseshell describe a coloring found in some cats but not a specific breed of cat. These markings can appear in many different types of cat breeds. Most calico cats are female due to the genetic factors which cause this coloring.
The Calico coloring is a mix of colors in different patches and a section of white. The colors are a mix of red based colors and black based colors. The patches can vary in size and pattern.
Tortoiseshell coloring differs from Calico in that a tortoiseshell cat has little or no white markings. In the UK instead of the word Calico they refer to cats with these coloration patterns and white markings as well as "tortoiseshell-and-white."
Calico colored cat pictured below:

An example of a Tortoiseshell colored cat: