I've been reading official BTC documentation and now I'm completely lost. Documentations is too tangled and written in unnecessary many words. They have:
https://en.bitcoin.it/wiki/Address
https://en.bitcoin.it/wiki/Accounts_explained (no, actually not explained)
https://en.bitcoin.it/wiki/Wallet
Please, somebody tell me the difference between them in a simple manner. What's an address, an account, a wallet, and how does the keys fit in.