大病医保的英文：
critical illness insurance program（重大疾病保险）

illness是什么意思：
n. 疾病

Many people are immobilized by the illness.
许多患上这种病的人都瘫痪了。

It becomes ill you to do so.
你这样做是挺不合适的。

They bear you no ill will.
他们对你并无恶意。

insurance是什么意思：
n. 保险；保险费；预防措施

The amount of a claim on an insurer by an insured.
险损赔偿额保险人从承保人获得的赔偿数量。

An insurance company will insure your house against fire.
保险公司愿为你的房屋保火险。

I have insured my car with a Japanese insurance company
我已向一家日本保险公司投了我的汽车保险。