The colloquial 'cleric' refers to any Cardinal Cleric, a religion common throughout the known worlds. However, the term is also often used to describe a sort of Battling Sorcerer similar to the Paladin. Due to the interchangeability of the terms, a "Battle Cleric" can be somewhat challenging to define.
In its purest form, a battle cleric is the ultimate balance between metal and magic. They wield enchanted weapons and wear magical armor, and fight in the name of the One King. What separates a battle cleric from a Paladin is the type of magic they use; clerics typically use common magics, while Paladins have paths of their own.