DSCR is short for debt service coverage ratio.
DSCR measures the ratio of available cash flow to debt payments (principal and interest). It is a measure used by banks and other lenders to be sure you have enough cash flow to pay your loans. Many times lenders will put in thier loan agreements requirements that a borrower maintain a certain DSCR ratio. These requirements are also known as loan covenants. Failing to maintain certain loan covenants could have some significant negative consequences (sometimes financial penalties or the potential of the loan being called).