Astrology is defined as the 'language of the stars,' with its basic terms including the birth chart, which serves as a unique map of an individual's personality and life potential based on the moment of birth. Key concepts include the moon sign, representing emotional response and inner self, the sun sign, indicating conscious personality and self-image, and the ascendant, which reflects how one appears to others. Together, these elements provide insight into strengths, weaknesses, and overall characteristics.