noun · verb · 4 senses · updated from the 2026-07-25 local source snapshot
Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.
Sound
Pronunciation
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/ˈkəʊstɑː(ɹ)/
Southern-England:Recorded audio is listed in the source snapshot.
CMU ARPABET:K OW1 S T AA0 R
Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
1
noun
Meaning 1
A person who shares star billing with another.
Definition source: English Wiktionary via Wiktextract
Definition source: English Wiktionary via Wiktextract
Usage: intransitive
Examples
People thought his career was over but now he will get to costar on Broadway next month.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
4
verb
Meaning 4
To feature (a number of star performers) jointly.
Definition source: English Wiktionary via Wiktextract
Usage: transitive
No example sentence was provided for this meaning.
Meaning relationships
Synonyms: none provided
Antonyms: none provided
History
Etymology
Etymology tree Proto-Indo-European *ḱe? Proto-Indo-European *ḱóm Proto-Italic *kom Proto-Italic *kom- Latin con- Latin co-der. English co- Proto-Indo-European *h2eHs- Proto-Indo-European *-tḗr Proto-Indo-European *h2stḗr Proto-Germanic *sternǭ Proto-West Germanic *sternō Proto-West Germanic *sterrō Old English steorra Middle English sterre English star English costar From co- + star.