World of Warcraft is a massively multiplayer online role-playing game (MMORPG) created by Blizzard Entertainment. The game takes place in a setting Blizzard has used for other games using the name "Warcraft". It has seven expansions, World of Warcraft: The Burning Crusade, World of Warcraft: Wrath of the Lich King, World of Warcraft: Cataclysm, World of Warcraft: Mists of Pandaria, World of Warcraft: Warlords of Draenor, World of Warcraft: Legion and World of Warcraft: Battle for Azeroth.

Warcraft: Orcs and Humans was a real-time strategy game. So were Warcraft 2 and its add-on, Warcraft 2: Tides of Darkness and Warcraft 3 and its add-on, Warcraft 3: The Frozen Throne. World of Warcraft is different than the other games because it is a MMORPG. This means that many people from around the world play together in the online world.

Players move through the game by gaining experience from killing enemies and finishing quests that are given throughout the game. If a player has enough experience, he will gain a level. There are 120 levels a player can get, which is made higher by each expansion by 10 or 5. They may continue to grow even more powerful at the highest level by getting items from bosses in instances and raids. World of Warcraft has developed a community of 'raiding guilds' that compete with each other for 'first kills' on bosses in new raid instances, dungeons that require 10 to 25 players to work together to take down really hard Alia  bosses.

Players are allowed to choose from a number of races and classes.

Humans look similar to human beings. Humans may choose from the following classes: warrior, rogue, hunter, paladin, mage, warlock, priest, and death knight.

Humans : Increased stealth detection, increased spirit, bonus reputation gain, good use of swords and maces, escape ability from trapping effects (Every Man for Himself).

Dwarves are short, scruffy, and enjoy their liquor. Dwarves may choose from the following classes: warrior, rogue, paladin, priest, hunter, warlock, mage, shaman

Dwarves : Stone form ability, higher critical strike rate with guns, higher frost resistance, treasure finding ability, good use of maces.

Gnomes are very short and mischievous and enjoy explosions and dangerous tools, their hair color may be pink or green or other colors. Gnomes may choose from the following classes: warrior, rogue, warlock, mage, and death knight.

Gnome : Escape ability from trapping effects (Escape Artist), increased intelligence, higher arcance resistance, bonus to engineering skill.

Night elves are tall and muscular. Their skin can be colored purple to pale white. Night elves may choose from the following classes: warrior, rogue, druid, priest, hunter, and death knight.

Night Elf : Ability to fade into the shadows (Shadowmeld), harder to hit, move faster while dead, higher nature resistance.

Draenei are tall blue creatures from the planet Draenor. Draenei may choose from the following classes: warrior, shaman, paladin, mage, priest, hunter, death knight.

Draenei : Bonus to jewelcrafting skill, may heal self or others over time (Gift of the Naru), bonus chance to hit, higher shadow resistance.

Worgen are werewolves that used to be humans. Worgen may choose from the following classes: Mage, Priest, Rogue, Warlock, Warrior, Druid, Hunter, and Death Knight.

Worgen : Bonus to skinning skill, may skin without skinning knife, increased shadow and nature resistance, bonus critical chance, may move faster for a short period of time (Darkflight).

Orcs are muscular, hairy, and green. Orcs may choose from the following classes: Warrior, Rogue, Shaman, Warlock, Hunter, and Death Knight.

Orc : Have the ability to enrage increasing damage output, resistant to stun effects, pet damage increased, good with axes and fist weapons.

Tauren are very tall, nature-loving cows that walk on two feet. Tauren may choose from the following classes: Warrior, Shaman, Druid, Hunter, and Death Knight.

Tauren : Have the ability to stomp stunning nearby enemies, bonus heath increase, herb gathering skill bonus, increased nature resistance.

Trolls are tall and can have large tusks, ranging from blue to green skin, with very colorful hair. Trolls may choose from the following classes: Warrior, Rogue, Shaman, Mage, Priest, Hunter, and Death Knight.

Troll : Ability to go berserk increasing attack speed, health regeneration bonus, increased damage against beasts, higher critical strike chance with bows and thrown weapons, slowing effects reduced.

Undead of the Forsaken faction are fairly short and pale with stringy hair, and their bones show through their clothing. Undead may choose from the following classes: Warrior, Rogue, Mage, Warlock, Priest, and Death Knight.

Undead : Ability to remove fear, sleep and charm effects, eat corpses to regenerate heath, underwater breathing increased, higher shadow resistance.

Blood Elves are of medium height and very thin, ranging in color from brown to pink to white. They have green eyes and long eyebrows. Blood elves may choose from the following classes: Warrior, Rogue, Paladin, Mage, Warlock, Priest, Hunter, and Death Knight.

Blood Elf : Ability to silence nearby opponents and restore energy, rage, mana and runic power, enchanting skill bonus, higher magic resistance.

Goblins are short, ugly, and green. They are very greedy and like to destroy things. Goblins may choose from the following classes: Mage, Priest, Rogue, Warlock, Warrior, Shaman, Hunter, and Death Knight.

In the game, there are classes.  Once a player has made a character, the character's class cannot be changed, but the character can be deleted. Players can have up to 50 characters on each account they pay for, and up to 10 characters per realm.

Note : There are three key roles in a raid / party group

Below is a list of classes available in World of Warcraft:

Mages cast spells using arcane, frost, or fire magic. Mages wear cloth armor and are very vulnerable to melee damage. They have access to massive ranged spell damage and area of effect capabilities.

Roles : DPS.

Rogues have a large number of escape tools to get away from battles they do not want to fight. Rogues can stealth (turn invisible) and stun their enemies in melee range, holding one weapon in each hand. Rogues use an energy bar

Roles : DPS.

Warriors can use nearly any one or two-handed weapon in the game, and may use shields. Warriors get angry (gaining "rage" when attacking enemies) and attack their enemies in melee range.

Roles : Tank, DPS.

Paladins may use 1 handed weapons and shields, or 2 handed weapons, they cannot dual wield. Paladins use holy magic via seal and judgment spells to attack in melee range, or they can be healers.

Roles : Tank, DPS, Healer.

Shamans wield the elements of nature and fire (and sometimes frost) spells. Shamans can use shields and can dual wield 1 handed weapons or use 2 handed weapons, and may fight in melee range, may cast from range, or may be healers.

Roles : DPS, Healer.

Warlocks cast shadow and fire magic spells. Warlocks wear cloth armor and are vulnerable to melee damage. Warlocks also summon demonic minions (pets) to help them in battle.

Roles : DPS.

Druids use arcane and nature spells, or may choose talents to be more of a melee fighter. Druids can shift into forms of animals like bear, cat, walrus, and cheetah. Healing druids can turn into a tree form, and the druid caster form is known as Moonkin.

Roles : Tank (Bear or Dire Bear Forms), DPS (Moonkin or Cat Forms), Healer (Tree Form).

Priests wear cloth and are vulnerable to melee damage. Priests can either heal with holy and discipline spells or do damage with shadow spells.

Roles : DPS, Healer.

Hunters attack with a bow, crossbow or guns from range while their pets attack and keep an enemy's hate in melee range. Hunters can tame many kinds of pets including spiders, bears, worms, wasps, and many more.

Roles : DPS.

Death Knights use runes and runic power to attack their enemies in melee range. Death Knights also have a number of ranged abilities to keep their targets from running away in battle.

Roles : Tank, DPS.

When a player gets to level 10, each level up afterward earns one talent point to be put into one of three class-specific talent trees. Different classes have different types of talents that are divided into three "talent trees", which are DPS (Damage Per Second), tanking (taking damage), and healing (healing damage). Putting points into the DPS tree may make them do more damage to enemies, putting points into the tanking tree may make them take less damage, while putting points into the healing tree may make them heal for more damage. However, a talent may not affect it directly.
For example, if a priest character wants to do more damage to enemies, the priest would put talent points into the "Shadow" talent tree. If a priest wants to heal groupmates, the priest would put talent points into the "Holy" talent tree.

Agility - This effects the characters dodge, critical strike and attack power (Although this is only true for certain classes).

Intellect - This determines spell critical strike, and how much damage your spells does.

Spirit - This increases the regeneration of health and mana.

Stamina - Increases the total amount of health you have.

Strength - Increases attack power and block value for a shield.

Armor - Reduces physical damage taken by a percentage.

Attack Power - Attack power increases the characters melee damage output.

Hit Rating - This increases the chance to it an enemy. This is capped at 14%.

Ignore Armour Rating - This enables the melee damage you cause to ignore a percentage of the opponents armor.

Critical Strike Rating - This effects your chance to cause additional damage on any melee attack.

Expertise Rating - Reduces the chance to be dodged or parried.

Attack Power - Attack power increases the characters Ranged damage output.

Hit Rating - This increases the chance to it an enemy. This is capped at 14%.

Ignore Armour Rating - This enables the Ranged damage you cause to ignore a percentage of the opponents armor.

Critical Strike Rating - This effects your chance to cause additional damage on any Ranged attack.

Hit Rating - This increases the chance to it an enemy. This is capped at 8% (So do not go overboard and get 21% like I did, it is a waste of gold).

Spell Penetration - This enables the Spell / Magic damage you cause to ignore magical resistance equal to the amount of spell penetration you have.

Critical Strike Rating - This effects your chance to cause additional damage on any Spell / Magic attack.

Speed Rating - Causes the cast time of your spells to be reduced. This is useless once it gets to one second, because of a global cooldown on all your spells.

Mana Regeneration - Increases your mana regeneration out of combat and while casting. This is very important for healers so that they do not OOM part way through a fight.

Bonus Damage / Bonus Healing - Some items specifically give you 'spell power' which is similar to attack power. Except it is separated into healing and damage. This is because some items give just these. Example: I help to kill a strong Boss, and I get a new robe. +23 spell power +30 healing power. (I am a DPS so I would give this to the groups healer instead.)

Defense Rating - Increases your likely hood to dodge, block and parry. This is very important for tanks to have. (With cata Changes now does not exist in game.)

Dodge - The ability to dodge an attack and suffer no damage. This is expressed as a percentage.

Parry - The ability to deflect an oncoming attack with your weapon. This is expressed as a percentage.

Block(Requires Shields) - The ability to block an attack with your shield reducing the damage you suffer from it.

Resilience - Reduces the damage players, and their pets cause you.

PvE - Stands for Player versus environment. Generally refers to all content in the game that is played against AI controlled units. This typically refers to raids and dungeons.

PvP - Stands for Player versus Player. Refers to all content in the game that is played with / against other human controlled units. Typically refers to Battlegrounds (rated and non-rated), Arenas and City Raids.

Mobs/Adds - A mob or add is a creature that is not player controlled. They are generally used in kill or collection quests. In Dungeons / Raids they can be used to swarm at your group, or to make the game a little bit more challenging. They do not often give very good loot, or experience.

Boss - A Boss is a creature that is not player controlled. They are mainly found inside Dungeons / Raids and are often very difficult to kill. Each Boss is a different fight and requires a large amount of skill and awareness to kill. Bosses give higher than average items, these can range from gear, to mounts and tokens.

Raid - A Raid is a specific area of the game, that is mostly cut off from the main world. The original World of Warcraft allowed up to 40 man Raids. Lately this has been reduced down to 10 mans and 25 mans. A Raid is a place to test your characters skills and interact with other players around the world. In each Raid there are Bosses and Mobs.

Dungeon - A Dungeon is smaller than a raid only being 5 man. Dungeons are designed to take people who have just reached the top level and give them better gear, so that they can start Raiding. Dungeons are also open to people who are still leveling. So that people can get better gear to make leveling faster, Or to complete quests that are inside Dungeons.

Threat - Threat is what causes a creature to attack a target. The Tank needs to generate enough threat to keep the Mobs / Boss attacking him. DPS also need to make sure they do not exceed the Tanks threat on the target. Example: I am a DPS, who is new. I cast lots of high threat spells during a Boss fight. The Boss turns around and kills me because I had more threat than the Tank. Since no one else had more Threat than the Tank the Boss re-focuses of him again. And I have to sit down and watch everyone fighting because I am dead.

Aggro - Aggro is when a Mob / Boss is focused on you. Example: The Tank losses aggro, because you were generating to much threat.

Tank - A person who protects the group by taking most of the damage and keeping the enemies attention. The Tanks generally need a specific amount of Defense, Dodge, and Parry to be allowed to tank higher levels of Raids. These people are always in demand.

DPS - Stands for Damage Per Second. These people are important for any Raid / Dungeon they are specialized in dealing high amounts of damage. DPS must not however cause too threat that they pull the Boss away from the Tank. This can prove fatal. DPS are never in demand because it is something all classes have the option to be.

Healers - A person who heals your Tank and your Party / Raid. These people are always in demand.

LOM/OOM - LOM means Low on Mana, this is not a very common phrase. OOM means Out of Mana, this is a lot more widely used in game. Energy has a fast regeneration and has a limit of 110 (with talents) 100 without. Rage and Runic power are also from a 0 - 100 scale, performing abilities and dealing damage grants more allowing more abilities to be used. Mana has no capped amount, the more Intellect your character has the more mana you have to play with.

CC - Stands for Crowd Control. Refers to all spells / abilities in the game that cause the target to be unable to perform certain tasks. Most commonly used in PvP but also widely used in PvE. Examples of CCs include: Stuns, Fears, Silences, Polymorphs, Cyclones etc.

LoS - Stands for Line of Sight. When there is an object or obstacle between the player in question and the target. Most commonly used in PvP as both a defensive tool (preventing spells to land and thus reducing damage and/or CCs) or an offensive tool (kiting an opposing player behind an obstacle and killing while preventing the opposing team's healer from being able to heal the target).

bio - Stands for Biology Break (i.e. bathroom break). Typically used in conjunction with "brb" (be right back) to inform the people in the party / raid that you will be right back after going to the bathroom.