What do you mean by coinsurance term?

Coinsurance is a percentage of what the insurance will pay to cover your health care cost after any deductibles or copays have been met.
If you have an insurance policy with a 80% coinsurance and a medical bill of $1,000, the insurance will pay 80% or $800 and your share of the cost would be 20% or $200 (assuming there is no deductible or copay on the plan)