Similar to what is commonly referred to as a wallet. In Beam it is a private account owned and operated by the user.

An account contains all of the user transaction accounting history, as well as the resulting current total balance. 

A Beam account is self-sovereign, which means that only the users can access and control their balance and that the full responsibility rests on them. The account is usually stored in the user’s computer.

This is achieved with public key cryptography, which has two separate keys: a public and a private key. The public key can be shared, and it can be used by the user to view the balance without any security risks. The private key must be stored securely, and only used when signing a transaction.