Accounts are not supported in the latest version of the wallet. The accounts were any way not part of the block chain protocol, they were part of the wallet software to ease people map address to a logical name which could help them relate the funds to logical names.
An address is a function of public key part of the key pair.
- An address doesn't identify an account. An account used to refer an address in wallet software.
- There exist no concept of server in blockchain, blockchain contains connected network of client referred as nodes running a common software following business rules. Each node manages complete copy of the ledger contains all the transactions performed between and by addresses.
- In short an address identify a functional identifier of a public key from a pair of public key and private key which is managed by the wallet software running in the node under your control/system.