Anatural monopoly's preemption of entry by other firms by exploiting its economies of scale is an example of

I believe the answer is: Barrier of entry

When one specific market is controlled by a big organization that possess the ability to utilize large number of resources, that organization could definitely create a cheaper product compared to smaller organizations who do not.

Because of this, a barrier is created for new organization who want to compete since it is impossible for them to take the big organization heads on in term of pricing.

repute barrier or barrier to entry.  

A natural monopoly's preemption of entry by other firms by exploiting its economies of scale is an example of barrier to entry.

This kind of monopoly is when a pre-existing business, who has a well established customer base, a good reputation in the market and cost effective prices sets up a monopoly because of its size, prices or power and causes a barrier to entry for all the new business who wish to enter.  

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