What is the difference between a secured loan and unsecured loan?

When you borrow money you will have either a secured loan, where the loan is secured against your property for example, or an unsecured loan where on default of payment the lender would have to take you to court to get the loan repaid.  

A mortgage is typically a secured loan in that if you default on payments the lender have the legal right to sell your home to recoup any losses. This is what is known a repossession.

Where you default on payments on an unsecured loans then the lender needs to take out a civil action in a court to recover their losses this could still eventually lead to the loss of your home, however less likely.