(n.) A male friend who attends upon a bridegroom and bride at their marriage; the best man.

acolyte adjutant agent aid aide aide-de-camp aider assistant attendant auxiliary bridemaiden bridesmaid bridesman coadjutant coadjutor coadjutress coadjutrix deputy executive officer groomsman help helper helpmate helpmeet lieutenant matron of honor paranymph paraprofessional second servant sideman supporting actor supporting instrumentalist usher wedding attendant wedding party