Security: legal concept ensuring enforceability by collateral or surety, providing creditor recourse and obligation assurance. Definition of security encompasses instruments or arrangements that make enforcement of a right more certain by furnishing assurance to a creditor, typically through a right over property or collateral such as pledges, mortgages, liens or documents evidencing indebtedness. The term also denotes a surety or guarantor who becomes responsible for another's obligations, reflecting both a property-based protection and a person-based assurance, and functioning to provide creditor recourse and indemnification rather than a strictly defined single legal meaning.