The Spanish word 'astro' meaning 'celestial body' traces its origins back through Latin to Ancient Greek. It comes from the Latin word 'astrum', meaning 'star' or 'celestial body', which itself was borrowed from the Ancient Greek 'ἄστρον' (astron), meaning 'star'. The word maintained its astronomical meaning throughout its evolution from Greek to Latin to Spanish, with only slight semantic broadening to refer to any celestial body rather than specifically a star.

Several common Spanish words are derived from 'astro', making it easier to remember. These include 'astronomía' (astronomy), 'astronauta' (astronaut), and 'astrología' (astrology). The prefix 'astro-' is commonly used in Spanish, just as in English, to form words relating to stars and celestial bodies.

English speakers will find it easy to recognize 'astro' as it appears in many familiar English words with the same Greek-Latin origin. Words like 'astronomy', 'astronaut', 'astrology', and 'astrophysics' all contain this root. The prefix 'astro-' in both languages maintains its connection to stars and celestial bodies. Even the name of the Houston Astros baseball team uses this same ancient root!