The word(s) "fortresses" appears 2 time(s) in 2 verse(s) in Quran in Mohsin Khan translation.

(1) "Wheresoever you may be, death will overtake you even if you are in fortresses built up strong and high!" And if some good reaches them, they say, "This is from Allah," but if some evil befalls them, they say, "This is from you (O Muhammad صلى الله عليه وسلم)." Say: "All things are from Allah," so what is wrong with these people that they fail to understand any word?

(2) He it is Who drove out the disbelievers among the people of the Scripture (i.e. the Jews of the tribe of Banu An-Nadir) from their homes at the first gathering. You did not think that they would get out. And they thought that their fortresses would defend them from Allah! But Allah's (Torment) reached them from a place whereof they expected it not, and He cast terror into their hearts so that they destroyed their own dwellings with their own hands and the hands of the believers. Then take admonition, O you with eyes (to see).