Insurable Interest and It's Definition Which is Taken From Wikipedia

The beneficiary who would suffer loss if the event insured against occurs. An insurance company will issue a policy by handed an insurable interest.
This is taken from http://en.wikipedia.org that Insurable interest exists when an insured person derives a financial or other kind of benefit from the continuous existence of the insured object. A person has an insurable interest in something when loss-of or damage-to that thing would cause the person to suffer a financial loss or other kind of loss.

For example, if the house you own is damaged by fire, the value of your house has been reduced, and whether you pay to have the house rebuilt or sell it at a reduced price, you have suffered a financial loss resulting from the fire. By contrast, if your neighbor's house, which you do not own, is damaged by fire, you may feel sympathy for your neighbor and you may be emotionally upset, but you have not suffered a financial loss from the fire. You have an insurable interest in your own house, but in this example you do not have an insurable interest in your neighbor's house.