What is the meaning of Security?

Generally speaking, a' Security' is a financial instrument that shows you own shares in a company (by owning stocks), have loaned money to a company, government, or municipality (by investing in bonds), or have rights to future ownership (as with options, rights, or warrants). Traditionally, securities were physical documents, such as stock or bond certificates. But with the advent of electronic recordkeeping, paper certificates have increasingly been replaced by electronic documentation.