what is an insurance replacement?

Answer 1

The cost of replacing something as opposed to paying the fair market (depreciated) value.

Answer 2

Your question is not specific enough. However, the term "Replacement Value" in insurance is the current value of the item at today's cost, not what you paid for ~ could be a vehicle or other personal property (homeowner policy).

If your policy provides Replacement Cost Coverage, usually an optional coverage that needs to be purchased, it means that you are entitled to the full replacement cost without depreciation.