noun
Refers to the systematic study or academic discipline of astrology, as opposed to the more general practice (占星術). Often used in scholarly or formal contexts.
See also: 占星術
彼は大学で占星学を専攻している。
He is majoring in astrology at university.
占星術 is the general practice or art of astrology (horoscopes, fortune-telling), while 占星学 emphasizes the academic or theoretical study of astrology.
Compound of 占星 (sensei, 'divining stars') + 学 (gaku, 'study, -ology'). The exact historical derivation is uncertain, but the term follows the common pattern of naming academic disciplines.