In a nutshell, Astrology is..
(1) An agricultural calendar that tracks seasons, weather, animal and plant cycles.
(2) An astronomical calendar that tracks the movements of the sun, moon & stars.
(3) A pagan cultural calendar that tracks and celebrates the passage of time.
(4) A mythology based on the anthropomorphization of astronomical objects.
(5) A symbol system / mnemonic device used to memorize & organize information.
(6) A time-based point system commonly known as horoscopes.

The latter definition is what is most commonly associated with astrology, however it is only one small aspect that can be ignored all together. There are two approaches to horoscopes, one is the symbolic (the point system is a game / calendar) the other is literalism (the point system = physics).
PS. The first approach is recommended and the latter is not.