According to Hebrew Kabbalistic doctrine, neschama is one of the three divisions of the Human soul. Neschamah means, and refers to the divine genius, or superconscious, associated with the realm of Atziluth. The neschama would be equivalkent to Thelema's Holy Guardian Angel.

Alternate Spellings: Neshama, Neshamah

Related Resources:

Introduction to Judaism
From your About.com guide to Judaism.

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The ABC's of Judaism
From Aish.com, and Rabbi Noah Weinberg.