(1) Safety; protection; the state of being protected from danger, loss, or threat. (2) Collateral; an item promised as a forfeit in case of default. (3) A stock, bond, debenture, or other interest that represents a share in ownership of a company or evidence of the company's indebtedness; an instrument that gives its owner the right to money or property; PL. securities. See also stock, bond, Securities and Exchange Commission