Definitions of security
a financial asset such as a share or a bond; the certificate that shows you own this financial asset
The safest, western government-backed treasury securities have seen the biggest gains.
property or goods that you deposit (=leave in someone's possession) or agree to give to someone if you cannot complete an obligation (eg if you cannot pay back money that you owe)
You can get a cheaper loan if you put your house up as security, but if you can't keep up the payments the loan company can sell your home.
protection against something bad that might happen in the future
Many analysts currently consider gold to provide the best financial security in the present market.