WordWeb Online

1. A friend who is frequently in the company of another
   "drinking companions";
   - comrade, fellow, familiar, associate, yokefellow [N. Amer]
    
2. A traveller who accompanies you
   - fellow traveler [US], fellow traveller [Brit, Cdn]
    
3. One paid to accompany, assist or live with another

1. Be a companion to somebody
   - company, accompany, keep company

Derived forms: companions, companioning, companioned

Type of: affiliate, associate, assort, attendant, attender, consort, friend, tender, traveler [US], traveller [Brit, Cdn]

Encyclopedia: Companion