The word(s) "strongholds" appears 3 time(s) in 3 verse(s) in Quran in Muhammad Pickthal translation.

(1) And seek ye out strongholds, that haply ye may last for ever?

(2) And He brought those of the People of the Scripture who supported them down from their strongholds, and cast panic into their hearts. Some ye slew, and ye made captive some.

(3) He it is Who hath caused those of the People of the Scripture who disbelieved to go forth from their homes unto the first exile. Ye deemed not that they would go forth, while they deemed that their strongholds would protect them from Allah. But Allah reached them from a place whereof they recked not, and cast terror in their hearts so that they ruined their houses with their own hands and the hands of the believers. So learn a lesson, O ye who have eyes!