astro-

1. a combining form with the meaning “pertaining to stars or celestial bodies, or to activities, as spaceflight, taking place outside the earth's atmosphere,” used in the formation of compound words.

   astronautics; astrophotography.

astro-

combining form

1. indicating a heavenly body, star, or star-shaped structure

   astrology

   astrocyte

2. indicating outer space

   astronautics

astro–

1. A prefix that means “star” (as in astrophysics), “celestial body” (as in astronomy), or “outer space” (as in astronaut).

Word History and Origins

Origin of astro–¹

< Greek, combining form of ástron a star, constellation, akin to astḗr star; aster, -aster ²

Word History and Origins

Origin of astro–¹

from Greek, from astron star

Example Sentences

The beloved People Mover would be no more, a Jules Verne-inspired art style would come and gradually go, and Buzz Lightyear Astro Blasters would arrive in 2005.

From Los Angeles Times

Brain cancer is - according to the Astro Brain Fund charity - the most fatal of all in terms of years lost, but investigations into it represent just 1% of the national spend on cancer research since records began.

From BBC

Astro Bot has swept this year's Bafta Games Awards, winning five awards in total - including the top prize of best game.

From BBC

Many had tipped Balatro - the poker-inspired card game made by an anonymous, lone developer known as LocalThunk - to pip Astro Bot to the award this year.

From BBC

A game envisioned to teach players about a console is not a new idea — see, for instance, the PlayStation 5 title “Astro’s Playroom” — and yet “Welcome Tour” took me back to mid-’80s PC work “Little Computer People.”

From Los Angeles Times

When To Use

What does astro- mean?

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.Astro- is also sometimes used to refer to something that is star-shaped, as in an astrocyte, a type of star-shaped cell in the brain and spinal cord.Astro- comes from the Greek ástron, meaning “star.” The Greek ástron is also related to such words as asteroid and even the star itself. The word astronomy comes from a Greek word that literally (and poetically) means “star-arranging.”What are variants of astro-?When combined with words or word elements that begin with a vowel, astro- becomes astr-.