An optical phenomenon in which light is refracted through a layer of hot air close to the ground, often giving the illusion of a body of water.
An illusion.
To cause to appear as or like a mirage.
A promise to pay a sum of money in the event that another person fails to fulfill an obligation.
One who undertakes to pay money or perform other acts in the event that his principal fails therein.
A substitute; a hostage.
Evidence; confirmation; warrant.
Certainty.
That which makes sure; that which confirms; ground of confidence or security.