1. an interest in a person or thing that will support the issuance of an insurance policy; an interest in the survival of the insured or in the preservation of the thing that is insured;
WordNet (r) 3.0 (2006):
insurable interest
n 1: an interest in a person or thing that will support the
issuance of an insurance policy; an interest in the
survival of the insured or in the preservation of the thing
that is insured