1、an arrangement with a company they agree to pay them fegular amounts of money and they agree to pay the costs,for examole,if you die or are ill/sick,or if you lose or damage sth.(保險)
2、the business of providing people with insuarance(保險業)
3、money paid by or to an insurance company(保險費)
4、insuarance against sth: sth you do to protect yourself against sth bad happening in the future(防備不測的保障措施，安全保證)