In Spain: a wrought-iron screen or grille used to protect windows, tombs, etc.
Late 18th century. From Spanish reja from Catalan rexa bar of a padlock, (in plural) bars of a window grille, (in singular) grille from Spanish Arabic rīša and Maghribi Arabic rīša, denoting various objects resembling a feather or parts of a feather (either the quill or the wing) in shape, e.g. (in Spanish Arabic) ‘tooth of a lock’, ‘spoke of a wheel’, (in Maghribi Arabic and other regional varieties) ‘stylus’, ‘iron nib’, ‘blade’, ‘pin’, ‘lancet’, etc., all transferred senses of literary Arabic rīša feather. Although a sense ‘grille’ does not appear to be attested in Arabic, it is conceivable that the sense ‘quill’ could have developed into ‘bar of a grille’ and hence ‘grille’ itself.