The words أَب a father; أَخ a brother; حَم a father-in-law, appended to a noun or to an affixed pronoun other than the first person of the singular, after rejecting the tanween decline by lengthening the preceding vowel, e.g. Nom. حَمُوهُ أَخُوهُ أَبُوهُ Acc. حَمَاهُ أَخَاهُ أَبَاهُ Gen. حَمِيهِ...