Principal
The amount you borrowed, or the part of your balance that is still owed, not counting interest.
When you take out a loan, the principal is the amount you receive. Each payment covers the interest that built up since the last payment, and the rest reduces the principal.
Paying extra toward principal lowers the balance that future interest is charged on. That is why small extra payments can shorten a loan and cut the total interest. Ask your lender to apply extra money to principal.
Example
On a loan with a $10,000 balance, a $300 payment that includes $60 of interest puts $300 − $60 = $240 toward principal. The new balance is $10,000 − $240 = $9,760.