ر س خr-s-kh
(ن) رَسَخَ يَرْسُخُ رُسُوْخًاrasakha yarsukhu rusūkhan: to be fixed firmly, to become settled, to be firmly established.
رَاسِخٌrāsikh pl. رٰسِخُوْنَrāsikhūna (active participle, ism fāʿil): firmly grounded, well established. ﴿وَالرّٰسِخُوْنَ فِي الْعِلْمِ﴾ (Āl ʿImrān 3:7)