Being a score that adds to a team's lead and makes it impossible for the opposing team to tie the game with its next score

ETYM From Insure.
Contract guaranteeing compensation to the payer of periodic premiums against loss (under stipulated conditions) by fire, death, accident, and the like. Various consumer policies also insure legal or health services, paying bills or portions thereof, within the contracted conditions. Insurance is a major component of business activity, covering potential loss of property, inventory, or goods in transit.
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; SYN. coverage.
During the Gulf War between Iran and Iraq 1987–88, it was the refusal of insurance companies to cover losses sustained by acts of war that dissuaded oil tankers from passing through the zone of hostilities.