Is third party guarantee a collateral security?

A third-party guarantee is not considered collateral security; instead, it is a promise made by a third party to fulfill a borrower's obligations if the borrower defaults. Collateral security typically involves tangible assets pledged by the borrower to secure a loan, which can be seized by the lender in case of default. While both serve to mitigate risk for lenders, they function differently in the context of securing loans.