Kabbalah literally means "receiving", and is sometimes transliterated as Cabala, Kabbala, Kabala, Kabalah, Qabalah, or other spellings."
The origins of the actual term Kabbalah are unknown and disputed to belong either to Solomon ibn Gabirol (1021 - 1058) or else to the 13th century AD Spanish Kabbalist Bahya ben Asher. While other terms have been used in many religious documents from the 2nd century AD up to the present day, the term Kabbalah has become the main descriptive of Jewish esoteric knowledge and practices. Main Kabbalistic literature which served as the basis for most of the development of Kabbalistic thought divides between early works such as Bahir and Heichalot (believed to be dated 1st Century AD) and later works dated to the 13th century AD, of which the main book is the Zohar representing the main source for the Contemplative Kabbalah ("Kabbalah Iyunit").
The study of the inner secrets of Torah (Sod) is called Kabbalah.
Torah study is traditionally divided into three levels, while Kaballah followers add a fourth: 1) Peshat, the surface meaning of the text; 2) Remez, allusions or allegories in the text; 3) Derash, a rabbinic or midrashic way of reading new lessons into the text; 4) Sod, the hidden mystical reading of the inner secrets of Torah. These hidden meanings are more than just what may be seen by attentive study, but include layer upon layer of codes and meanings intentionally hidden by God, which can only be found through unraveling coded meanings.
Kabbalah is considered by its followers to be part of the study of Torah - the study of Torah (the Law of God) being an inherent duty of observant Jews - specifically the study of the inner meaning of Torah. The Torah is the name commonly given to the first five books of the Hebrew Bible which is also the Christian Old Testament. These first five books are commonly referred to in Christian circles as the Pentateuch.
"Kabbalah refers to a set of esoteric teachings and mystical practices that form an alternative to traditional Jewish interpretations of the Tanakh and religious observances. It is a set of beliefs followed by some Jews as the true meaning of Judaism, while rejected by other Jews as heretical and contrary to Judaism.