In Arabic philosophic texts, and following them also in Hebrew philosophic texts, restatements of Aristotle's distinction between ‘equivocal’ (ὁμώνυμα, mushtarakah) and ‘univocal’ (συνώνυμα, mutawāṭi'ah), terms usually contain another type of term which stands midway between these two. It is called ‘ambiguous’ or ‘amphibolous’ (mushakkikah) terms. So far no adequate explanation as to the origin of this type of term has been advanced. In the latest and most important study of the subject, the problem of its origin has been left unsolved. To solve this problem as well as to account for the various treatments of ambiguous terms in Arabic philosophy, including Alfarabi, Avicenna, Algazali, Averroes and Maimonides, is the purpose of this paper.