Abbreviation of 占星術 (せんせいじゅつ). Used in compounds or as a shorter alternative in contexts where the full term is understood.
See also: 占星術
彼女は占星に詳しい。
She is knowledgeable about astrology.
I checked today's fortune in the astrology section.
astrology
astrology
astrologer
Abbreviation of 占星術 (せんせいじゅつ), from 占 (divination) + 星 (star).