Difference between Custom tab and Visualforce Tab in Salesforce?

Hi Suraj,

A custom tab is the way to read the object’s records.You can have a custom object without having an associated tab
You can’t have a custom tab without an associated custom object.

There are different types of custom tabs, so it is possible to have a custom tab without an associated custom object (web tabs, visual force tabs, etc).

https://help.salesforce.com/apex/HTViewHelpDoc?id=dev_tabdef.htm

Thanks.