The Hebrew word shanah ‘to repeat’ in its technical sense means to learn (e.g. Abot 2.4; 3.3) or teach (e.g. Erub 54bb) oral tradition by repeated recitation, in contrast to qara’, to study the Holy Scriptures. The Aramaic equivalent is teni or tena’, the derivative noun is mishnah or matnita’.
Mishnah, therefore, means study (m.Abot 3.7) as well as oral instruction (t.Ber 2.12, L. 8). In this sense, the Mishnah comprises the three branches of tradition: midrash as the interpretation of the text of Scripture; the halakhot as the statutes formulated independently of Scripture; and, finally, the haggadot, i.e. all non-halakhic material. Thus, a baraita in Qid 49a answers the question, ‘What is Mishnah?’ R. Meir says, ‘Halakhot.’ R. Yehudah says, ‘Midrash’ (cf. further Finkelstein).
More specifically, Mishnah designates the entire religious law formulated until c. 200, but also the teaching of a teacher (Tannaite) active in this period, as well as an individual proposition (=halakhah) or collections of such propositions (e.g. p.Hor 3, 48c mishnayot gedolot, the great mishnaic collections such as the Mishnah of Hiyya [read thus instead of ‘Huna’ in printed editions], of Hoshaya and of Bar Qappara). The Mishnah par excellence is the collection attributed to R. Yehudah ha-Nasi, with which we are here concerned.
H.L. Strack and Günter Stemberger, Introduction to the Talmud and Midrash, trans. and ed. Markus Bockmuehl, 2nd ed. (Minneapolis: Fortress Press, 1996), 109.