One of the Oxford Dictionaries definitions of ACCOUNT is "a report or description of an event or experience".
An ACCOUNT then is a collection of information that relates to one or more EVENTs. Those EVENTs will have an ITEM in common in a role and thus the ACCOUNT becomes a history of information about that role.
Examples
* A Customer Account at a business * The history of a Building * Regular welfare payments to a claimant * A Medical History of a patient * Transactions that have been posted to a budget.