promise of reimbursement in the case of loss; paid to people or companies so concerned about hazards that they have made prepayments to an insurance company(noun.possession)
source: wordnet30
written contract or certificate of insurance(noun.communication)
The act of insuring, or assuring, against loss or damage by a contingent event; a contract whereby, for a stipulated consideration, called premium, one party undertakes to indemnify or guarantee another against loss by certain specified risks. Cf. Assurance, n., 6.(noun)