Hostage (noun)

1. A person who is held by one party in a conflict as security for the compliance of another party.
2. A person who is taken or held as a prisoner in order to force someone else to do something.
3. A person or thing that is used as a guarantee for the fulfillment of a promise or the payment of a debt.

Origin:

Late middle english (in the sense "pledge, guarantee"): from old french hostage, from late latin hostaticum, from latin hostis "stranger, enemy".

Examples:

1. The terrorists demanded the release of their comrades in exchange for the hostages.
2. The hostages were held captive for several months before being released.
3. The kidnappers threatened to kill the hostages if their demands were not met.
4. The government negotiated with the terrorists for the release of the hostages.
5. The bank used the loan collateral as a hostage to ensure the borrower's repayment.