Home equity is the the difference between how much is owed on a mortgage and what the value of your home is. If you have a home that is worth $500,000 and your the amount you owe on your mortgage is $350,000, then you have $150,000 worth of equity in your home.
It is very common to access the equity in your home with a home equity (fixed) loan or a home equity line of credit, or HELOC. A HELOC allows you to draw money out of your equity balance up to your limit and make payments on the outstanding balance.
Your home is the largest savings account that you probably have. If you need to take some cash-out to make improvements, a major purchase, or pay off all of your credit card debt, you should use the equity in your home wisely.
Your homes equity can be taken out in the form of a loan and used for a variety of purposes.
Be careful about using your equity as if its your own personal ATM. Home Equity is not the same as cash because its value can fluctuate. Any cash taken out of your home's equity should be spent adding value to the house (pool, deck, guest house, etc) or to pay off high interest consumer debt (credit cards, car loans, etc). If you spend the cash from the equity in your home frivolously you may end up "underwater", or owing more than the home is worth.