The definition of a fortress is a secured and strong place.noun
An example of a fortress is a wall made out of stone that protects a city.YourDictionary definition and usage example. Copyright © 2013 by LoveToKnow Corp.
Origin: ME forteresse < OFr < VL *fortaricia < L fortis, strong: see fort
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Origin: Middle English forteress, from Old French, from Medieval Latin fortalitia, from Latin fortis, strong; see bhergh-2 in Indo-European roots.