'aster' originates from Greek, specifically the word 'astḗr' (ancient Greek 'ἀστήρ'), where 'astēr' meant 'star'.

'aster' passed into Latin as 'aster' and later into Medieval and Modern English with the same form; the botanical name and the biological term were formed from this root, reflecting a 'star‑like' shape.

Initially it meant 'star'; over time the term was extended metaphorically to objects or structures that are star‑shaped (for example, certain flowers and mitotic microtubule arrays).