What does the term, deductible refer to in health insurance?

Could someone help explain this to me in context details please??? I kind of understand that it means...That I pay a that set amount stated before the covered amount of my health insurance takes affect...But my question mostly concerning is, when do I pay the deductible? Like, would I have to pay a deductible you think when I just need to go to the ER to get an X-Ray or just make an office visit you think and would that be every time I go as well?
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Hi. If your health insurance plan has a deductible you are responsible to pay for services until your deductible is met. After your deductible is met, your insurance company will pay a percentage of the bill after that and you will have a percentage as well (for example, if you have an 80/20 plan, your insurance company will pay 80% of the allowed amount of the claim and you will be responsible for paying 20%). There are certain services, that are excempt from being applied to your deductible, such as doctor office visits, routine or preventative care services that your insurance company will most likely pay and these services will not be applied to your deductible. Other services, such as the x-ray you mentioned in your question, would be applied to your deductible. Your insurance company will keep track of how much was applied to your deductible. The Explanation of Benefits you receive in the mail from your insurance company for services you receive will let you know if the insurance company paid for the service or if all or part of the service was applied to your deductible. I used the term allowed amount above. The allowed amount is the contracted rate between the physician and the insurance company, if the physician, healthcare professional or healthcare facility is in-network and accepts your insurance. Some insurance companies will apply the allowed amount to your deductible and the doctor's office will write off the difference between the allowed amount and their billed charged about or some insurance companies may apply the total billed amount (unless the physician's office charges way above what is considered usual and customary for that service) to your deductible.
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