Bitcoin - differences between address, account and wallet
"Accounts" are a concept limited to bitcoin-qt, and it's probably better to forget about them entirely.

Each address has a corresponding private key, that you use to move bitcoin out of that address. A wallet is simply a collection of (address, address_key) pairs.

Some people also use the term "wallet" to refer to the software that implements the wallet functionality.



Obviously, this is a grossly simplified answer, and not strictly true, but useful if you just want to understand bitcoin superficially.