Astro- is a combining form used like a prefix meaning “related to stars, celestial bodies, and outer space.” It is often used in scientific terms, especially in—you guessed it—astronomy.

Does astronomy have a suffix?

Both astrology and astronomy have Greek roots, and they share the prefix astro- which means, of course, "star." The suffix -ology means "knowledge" or "science." ... Astronomy is, strictly speaking, the measurement of the positions of the stars and planets, "ordering the stars," so to speak.

Is astrology and astronomy the same thing?

Astronomy is a science that studies everything outside of the earth's atmosphere, such as planets, stars, asteroids, galaxies; and the properties and relationships of those celestial bodies. ... Astrology, on the other hand, is the belief that the positioning of the stars and planets affect the way events occur on earth.