The word "collateral" primarily refers to an asset or property that a borrower offers to a lender to secure a loan. If the borrower fails to repay the loan, the lender has the right to seize the collateral to recover their losses. In a broader sense, "collateral" can also mean something that is secondary or additional but related to the main issue or event.
The word "collateral" comes from the Latin word "collateralis," which means "lying at the side" or "additional." It is formed from "com-" (together) and "lateralis" (of the side).