companion

(noun) a friend who is frequently in the company of another. Synonyms: comrade, fellow, familiar, associate. Examples: "Drinking companions." "Comrades in arms."

(noun) a traveler who accompanies you. Synonyms: fellow traveler, fellow traveller.

(noun) one paid to accompany or assist or live with another.

(verb) be a companion to somebody. Synonyms: company, accompany, keep company.