A home equity line of credit is a form of revolving credit in which your home serves as collateral. Because the home is likely to be a consumer’s largest asset, many homeowners use their credit lines only for major items such as education, home improvements, or medical bills and not for day-to-day expenses. With a home equity line, you will be approved for a specific amount of credit--your credit limit, the maximum amount you may borrow at any one time under the plan. Read more on the Federal Reserve's website.
What You Should Know about Home Equity Lines of Credit (Federal Reserve Board)