Cleric

Warrior priests who command the will of their chosen domains through the governing deities to perform miracles and might.

Paladin vs. Cleric

It is common to conflate the two as being "the same," or paladins being the "bruisers" and the clerics being the "healers" or a common adventuring group. This can be the case, but the actual distinction is in their philosophy. Clerics serve domains (Life, War, Knowledge, etc.) and paladins serve deities (i.e. Moradin, Bahamur, Pelor, etc.) In many scenarios they may hold similar views, such as dispatching undead if the paladin serves the Raven Redeemer or some other undead-defying deity. It can also cause conflict if the cleric perceives an issue to be under the domain of several deities and the paladin believes it to be under their deity.