What is the difference between secondary and supplemental insurance?

Some might say...symantics. But as a supplemental insurance agent, what it means to me is:

Secondary = a policy that typically pays the provider's remaining medical bills that a primary insurance policy did not pay. Sometimes a secondary policy will pay 100% of the leftover medical bills and sometimes it will only pay for the coinsurance portion and not the deductible (for example). This happens often when a husband & wife both take their employer's health insurance policy and cover each other. The spouse's insurance policy would pay secondary.

Supplemental = a policy that pays the policyholder to offset out-of-pocket expenses in general. Careful that your policy isn't full of the Words "pay incurred charges" or "pay up to incurred charges" as it is a way to limit the actual benefit at time of claim. There's plenty of policies out there that will state a lump sum paid because "a" or "any" charge is incurred. The idea is that your co-payment and deductibles or no health insurance at all is only the tip of the iceberg if your dealing with a serious injury or illness. This usually means theirs and interruption of income with 83% of the population living paycheck-to-paycheck then it doesn't take long for it to become difficult to maintain the household bills.