What is Further Advance?

Legal Definition
A second or subsequent loan of money to a mortgagor by a mortgagee, either upon the same security as the original loan was advanced upon, or an additional security. Equity considers the arrears of interest on a mortgage security converted into principal, by agreement between the parties, as a further advance. Wharton.
-- Black's Law Dictionary
Legal Definition
A further or additional loan to a mortgagor, often secured by the original mortgage.
-- Ballentine's Law Dictionary