a person who is frequently in the company of, associates with, or accompanies another

my son and his two companions.

a person employed to accompany, assist, or live with another in the capacity of a helpful friend.

a mate or match for something

White wine is the usual companion of fish.

a handbook or guide

a bird watcher's companion.

a member of the lowest rank in an order of knighthood or of a grade in an order.

Also called companion star , comes. Astronomy . the fainter of the two stars that constitute a double star. Compare primary ( def. 19b ) .

Obsolete . a fellow.

to be a companion to; accompany.

noun

enemy , foe , foreigner , opponent , stranger

noun

accompaniment , accomplice , aide , ally , assistant , associate , attendant , buddy , chaperon , colleague , comate , complement , comrade , concomitant , confederate , consort , convoy , counterpart , cousin , co-worker , crony , cuz , double , escort , guide , match , mate , nurse , pal , pard , partner , playmate , protector , roomie , safeguard , sidekick , chum , fellow , duplicate , twin , accessory , alter ego , amigo , boon companion , camaraderie , chaperone , cohort , commensal , commensality , compadre , compeer , confrre , duenna , esprit de corps , friend , husband , intimate , matey , peer , sibling , spouse , wife

verb

attend , company , escort