A keyword is a principle, an archetype related to a given astrological sign, one of its main characteristics. Samael Aun Weor provided keywords for each zodiac because these are the chief characteristics given to any particular sign, and can help us to understand, given the context of each chapter, what we need to develop and overcome within ourselves.

Fecundation has to do with fertility, growth, childhood, innocence, and spiritual creation. It is necessary for individuals from the sign of Cancer to cultivate their lost childhood through fecundating the consciousness; they must become fertile in the great work and overcome too much lunar sentimentality and emotionalism.

Keywords help us understand our innate zodiacal tendencies in order to develop our essence through conquering our ego and personality. Each zodiacal sign has a positive and negative crystallization; the keywords help us understand such chief characteristics within ourselves, in this given life under a specific sign, in order to aide us in self-knowledge.