Definitions for "Non-renewable resource"
a resource which is not readily replaced by nature when it is used up (Examples of non-renewable resources are iron, copper and nickel.)
A resource that is NOT capable of being naturally restored or replenished; a resource that is exhausted because it has not been replaced (e.g. copper) or because it is used faster than it can be replaced (e.g. oil, coal [what we call fossil fuels]). Their use as material and energy sources leads to depletion of the Earth's reserves and are characterized as such as they do not renew in human relevant periods (They are not being replenished or formed at any significant rate on a human time scale).
A natural resource which can only be used once and cannot be replaced once it is used up, eg coal, oil and natural gas.