An account can be many things — such as a story, like if you give a friend an account of what happened at the party she missed. It can also be a business arrangement, like a bank account or an email account.
Account is one of those seemingly simple words that have a mass of different meanings. An account can be a narrative or story — a biography, for example, is an account of someone's life. Account can also mean an explanation of something, as in the phrase, "How do you account for that?" An account is also a handy arrangement whereby a store agrees to provide you goods on credit, but then you might have to account for all that debt.