A mortgage that is subordinate to the first mortgage.
In the event of foreclosure, the first mortgage holder has the right to be
repaid in full before second mortgage holders receive any payment.
If insufficient sums are available to fully repay the first mortgage holder,
then the second mortgage holder will receive nothing.
A third mortgage is subordinate to the first and second mortgages.
The interest rate for second mortgages is higher than for first mortgages
since the first mortgage has priority in payment.