Sefer HaMiddot Rubin

Sifrei Kodesh, commonly referred to as sefarim, or in its singular form, sefer, are books of Jewish religious literature and are viewed by religious Jews as sacred. These are generally works of Torah literature, i.e. Tanakh and all works that expound on it, including the Mishnah, Midrash, Talmud, and all works of Musar, Hasidism, Kabbalah, or machshavah. Historically, sifrei kodesh were generally written in Hebrew with some in Judeo-Aramaic or Arabic, although in recent years, thousands of titles in other languages, most notably English, were published. An alternative spelling for 'sefarim' is seforim.