OD account stands for Overdraft account. It is a type of account in which you can withdraw amount even if there is no fund in your account. The bank sanctions a specific limit and your account can go in negative up to that limit. You have to pay interest only on the amount taken as loan. Since it is a current account, you can make as many transaction as you want. You have to pay interest on the amount which is due by the end of the day.
Overdraft and Cash Credit account both are the type of loan accounts in which the account holder can withdraw the amount he requires . These generally are considered as similar type of loan by many,yet there are some differences between them.