The Torah or Law is divided into five books, and is therefore called
חומש or Pentateuch (Fivefold or Five-book). The names of the five
books are: (1) בראשית Genesis (Creation); (2) שמות Exodus
(departure, scil., of the Israelites from Egypt); (3) ויקרא Leviticus
(on the laws concerning the Levites or priests), also called תורת
כהנים “law of the priests;” (4) במדבר Numbers; (5) דברים
Deuteronomy, a Greek term denoting “second-law” or “repetition of the
law,” a translation of the Hebrew משנה תורה.
These names are derived from the beginnings of the books. The Hebrew
names are either the first word of the book, as is the case in the
first and the third books (בראשית and ויקרא), or the first
characteristic word, as is the case in the other three books (שמות
the second word, במדבר the fifth, דברים the second). The English or
Greek names describe the subject-matter of the first section of the
book. This applies also to the rest of the Biblical writings.