Marit ayin
Mar'it-ayin (Mish.: מַרְאִית הָעַיִן; Modern Hebrew: מַרְאִית-עַיִן 'appearance to the eye'; Ashkenazic transliteration: maris ayin), is a concept in halakha (Jewish law) which prohibits certain actions which might seem to observers to be in violation of Jewish law, even if they are in fact permissible, in order to prevent onlookers from drawing false conclusions. For example, according to the Torah law it is forbidden to eat the blood of an animal, but the blood of fish is permissible.