One should be familiar with the meanings of terms that are frequently used by the muhaddithin. They are: hadīth, khabar, athar and Sunnah; from the perspective of the terms of hadīth and its transmission: matn, sanad, isnād, musnad and musnid; from the perspective of the transmitters: muhaddith, hāfidh, hujjah and hākim. As for the exposition of the meanings of these words in the terminology of hadīth, then it is as follows:

1. Hadīth: Whatever has been attributed to the Prophet  of his sayings, actions, consent or physical attributes i.e, relating to his creation such as his not being tall nor short, or his character, that is, relating to his character such as his [not countering anyone with anything makrūh]. Khabar and Sunnah have this same meaning. They are synonymous with the term hadīth. All of them, i.e, hadīth, khabar and Sunnah have the same meaning. As for athar it is the hadīth stopping [mawqūf] at the Sahābah .

2. Matn: The speech which comes at the end of the highest part of the sanad. The sanad is the path leading to the matn which is the men (transmitters) who lead to it. The isnād raises (links) the hadīth to the one who said it. Musnad is that (hadīth) whose chain connects its beginning to its end (without any breaks) even if it is mawqūf. The word musnad is also applied to a book in which transmissions of the Sahabah are collected. As for musnid it is the person who narrates the Hadith with its isnād.

3. Muhaddith: someone who carries the hadīth and devotes his attention to it in terms of its transmission and meaning. The hāfidh: someone who has committed to memory a hundred thousand ahadīth with the matn and sanad even if through various lines of transmission and he is aware of what he requires. The hujjah: someone who is thoroughly acquainted with three hundred thousand ahadīth; and the hākim: someone who is thoroughly acquainted with the entirety of the Sunnah.