Astr
Astr is a combining form used in English to denote relation to stars. It derives from the Greek word astron meaning star and entered English through Latin and later scientific vocabulary. In contemporary usage the form appears in two spellings, astr- and astro-, and is productive in many star-related terms.
Common derivatives include astronomy, astronomer, and astronomical, which refer to the science of celestial objects, their
Related forms include aster- words such as asteroid and asterism, which come from a closely related root