A HELOC is an acronym for Home Equity Line of Credit and is a revolving credit line to allow access to a portion of the available equity in the home. A HELOC can be the only mortgage on a property but is usually a second mortgage/portion attached to or behind a standard mortgage that has a regular principal and interest payment. A HELOC can also increase in size if it is attached to the standard first mortgage and grows by the amount of the principal paid down on each regular mortgage payment.