Bind

Many items in the game can bind to a character or account, restricting them from being transferred to other characters. Once an item is bound, it will either be soulbound or account-bound. Bound items can't be traded, auctioned, or mailed to other players. Soulbound items can't be transferred to other characters in any way, even characters owned by the same player (alts of that player). Account-bound items, on the other hand, can be mailed between characters on the same game account, even after equipping those items.

If an item has any binding, its tooltip will clearly state whether it is bound yet and which type of binding it uses.

Some new players might be a little apprehensive when they first see "Using/equipping this item will bind it to you". There is no need to fear, the item is simply bound to the inventory of your character - not stuck on or to your character. You can still unequip it, put it in your bank, or sell it to a vendor.

Binding types
Unbound items can be:
 * Bind on Equip (BoE): Items of this type become Soulbound to the first player to equip the item. Until then they may be traded freely, just like with non-binding items.
 * Bind on Pickup (BoP): These items become Soulbound to a player as soon as they are picked up. A warning appears before making a loot roll or picking up a BoP item when using a group loot system.
 * Bind on Use (BoU): Items of this type become Soulbound after first use. This is used for objects that are used but do not need to be equipped, which was formerly common on items which were converted into Collections entries, and is now much rarer. A warning will appear before an unbound BoU item is used.
 * Bind to Account (BtA or BoA): Items listed this way bind on pickup much like BoP items, but will become account-bound instead of soulbound. When looting in a group it's essentially the same as BoP - the player should confirm they don't want to let another player have the item. Note that all account-bound items bind this way, never on equip or on use.
 * Does not bind: These items can freely change hands. Examples of this are recipe materials and most consumables such as health and mana potions, health stones, food, and water, etc. (There is no label for this type; items behave this way unless otherwise noted.)

Items that have become bound in some way are one of:
 * Soulbound: Soulbound items have already been "locked" to a character, meaning they cannot trade, auction, or mail the item to any other character. It can still be vendored, put in a bank, and so on as long as it doesn't go to another character.
 * Blizzard Account Bound: This describes items that have been bound to one Battle.net account, but not to a single character. They are restricted like soulbound items with the exception that they can be mailed between characters in the same account. Account-bound items never become soulbound, even after being equipped - they can still be unequipped and mailed to an alt later. (This doesn't include item types that can't be unequipped at all, like mount equipment or consumable items.)
 * Quest item: Quest items have the same restrictions soulbound items have. Additionally, they usually can only be acquired when a quest is active, and disappear when that quest is completed.