A suppplemental loan with a maturity that is the same as the senior, or original, loan. Coterminous is most often used to describe mortgage loans, such as those for residential and commercial borrowers.
Investopedia Says:
While a supplemental loan can have a maturity date that occurs after that of the original loan (often called "non-coterminous"), most second mortgage lenders or mezzanine lenders prefer to have both loans mature on the same date. This way, the borrower can choose to refinance both loans into one larger one, preferably with the same lender.
