Nomenclature
Tanks were known by one of three identification schemes. Firstly a General Staff specification e.g. A13. This could apply to more than one vehicle or if the vehicle was privately developed not have a General Staff number at all. Secondly by a descriptive name - e.g. "Tank, Infantry, Mark II". This scheme was introduced during the war and not always retrospectively applied to earlier designs. The descriptive name could also be modified by the inclusion of "A" denoting an armament change or "*" donoting some other change. Thirdly by a name - e.g. Crusader.
Read more about this topic: British Armoured Fighting Vehicle Production During World War II