ʿUlūm al-Ḥadīth, as it was more commonly referred to in classical works, or Muṣṭalaḥ al-Ḥadīth as it is more commonly known today, is defined as:

“…the knowledge of the principles and maxims by which the conditions of chains of narrations and texts are known, in terms of acceptability and rejection.”

See: Maḥmūd al-Ṭaḥḥān’s Taysīr Muṣṭalaḥ al-Ḥadīth, (Alexandria: Markaz al-Maʿhad li al-Dirāsāt, 1415H), p. 15.