Concerning the definition of tiryañc in the Abhidharma, the first mention is in the Saṅgītiparyāya集異門足論. This includes the definition of tiryañc inherited in subsequent treatises in the Sarvāstivāda. However, a comparison of definitions of tiryañc in the *Abhidharma Mahāvibhāṣa 阿毘達磨大毘婆沙論 and the *Abhidharmavibhāṣā 阿毘曇毘婆沙論 reveal some differences. Considering these differences, the definition of tiryañc in the Saṅgītiparyāya may have been introduced later, under the influence of later Abhidharma treatises. In addition, this paper discusses the older form of the definition of tiryañc by comparing Āgamas and Abhidharma treatises. As a result, it became clear that the definition indicating the location in which living beings were reborn by bad physical, verbal and mental karma is old.
