companion

nouns

a friend who is frequently in the company of another
"drinking companions"; "comrades in arms"
associate, companion, comrade, familiar, fellow
is derived from
companionship
a traveler who accompanies you
companion, fellow traveler, fellow traveller
is derived from
companionship
one paid to accompany or assist or live with another
companion
is a type of (narrower)
someone who waits on or tends to or attends to the needs of another
attendant, attender, tender

verbs

be a companion to somebody
accompany, companion, company, keep company