What does in debit mean ?

When an account has been debited, money has been taken out of it. Firms use double-entry accounting to get the balance sheet; the first is the debit entry.  

Accounts having positive balances receive debits, and these are called positive accounts. Conversely, if the accounts and liabilities are maintained in a negative balance, you get credits for it. 

The opening balance of a new financial year can be in debit or credit, depending on various factors; hence, it shows on either side of the ledger.