Barbarian

The term "barbarian" comes from the ancient Greek "Barbaroi," and is used to designate an uncivilised person or a person of an inferior culture. In reality, practically all foreigners or those who did not speak Greek were deemed to be "barbaros" and sometimes the term was used even for Greeks from other states. Later on, the term came into used mostly to designate the migrating tribes that conquered Rome during the dark ages and after that it referred to Goths and Vikings more specifically.

Barbarian characters have been a staple of fantasy at least since Conan the Barbarian (ie. since the beginning) as "noble savages" who impress with their might and courage. Today, barbarians in fantasy retain this image of a savage warrior, clad in simple or primitive clothing that rely more on brute strength and chaotic violence than any precise fighting style or cunning.

Barbarians are usually the subjects of the best fantasy movies. Conan the Barbarian and The Barbarians as well as Fire and Ice are excellent examples of awesome, cheesiness, and awesomeness and gayness, respectively.

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  The comics dumbed down the original Conan, who was not a stupid muscle-man but also a thief and a wise ruler. Though still he was primarily a man of action, rather than a man of thought.
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  A modern day barbarian activating his Rage.
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  Turning people into barbarians since 1982.

GARRRRRR!!!! I SMASH YOU WITH GREATAXE FOR 1d12+STR*1.5 DAMAGE! (interestingly, great axes and 1d12 weapons weren't in Dungeons and Dragons 2e and 1e horrible, isn't it? You could only deal 1d12 or better if you were attacking a size Large creature.)

Barbarians in D&D 3.5

d12 hit points, uncanny dodge, illiteracy, and can fly into a rage for some stat bonuses at the expense of AC and passes out when the fight is done. Unless you get Tireless Rage... They mesh well with Frenzied Berzerker as a prestige-class. Too bad Frenzy sucks (Bullshit, with Frenzy you can keep on fighting even when your hit points are like negative thirty billion as long as the frenzy hasn't ended yet.) Supreme Cleave and Supreme Power Attack are must haves though. See for yourself. While the Frenzied Berserker attacking your allies due to a class feature seems bad, a successful calm emotions spell should prevent conflict (provided it is cast before the Berserker has a chance to turn on his friends, and it lasts long enough enough that the frenzy runs out of turns). Hopefully the DM will even allow you to voluntarily fail your saving throw against it.

Barbarians in Pathfinder

A lot like 3.5 barbarians, with the loss of illiteracy (unless your archetype forbids reading), the addition of trap sense (pfffffff), and, the major differene and draw, rage powers.

That's right, every two levels your barbarian bro learns a new way that getting really fucking angry can give him superpowers. These powers range from the useful (making combat maneuvers in place of regular attacks) to the impractically awesome (beating an opponent with another opponent) to the outright supernatural (sprouting claws and horns before gaining a pounce attack) to the hilarious (gaining big bonuses on swim checks).

...That last one makes sense mechanically (rage buff strength, after all, and strength is the stat used in swim tests), but the mental image is never not funny. ("FUCK YOU WATER! WRAAAAAAAA!")

The Classes of Pathfinder 1st Edition
Core Classes:	Barbarian - Bard - Cleric - Druid - Fighter - Monk Paladin - Ranger - Rogue - Sorcerer - Wizard
Advanced Player's Guide:	Alchemist - Antipaladin - Cavalier Inquisitor - Oracle - Summoner - Witch
Advanced Class Guide:	Arcanist - Bloodrager - Brawler - Hunter - Investigator Shaman - Skald - Slayer - Swashbuckler - Warpriest
Occult Adventures:	Kineticist - Medium - Mesmerist Occultist - Psychic - Spiritualist
Ultimate X:	Gunslinger - Magus - Ninja - Samurai - Shifter - Vigilante

Barbarians in other Things

Warhammer Fantasy - Warriors of chaos

Warhammer 40K - World Eaters, Space Wolves, White Scars