companio

Latin

From con- (“with”) +‎ pānis (“bread”) +‎ -ō (noun-forming suffix), a calque of Proto-West Germanic *gahlaibō (“messmate”, literally “person with whom one shares bread”). First documented in the Lex Salica.^[1]

compāniō m (genitive compāniōnis); third declension (Late Latin)

Via the nominative compāniō:

Italo-Romance:
- Corsican: cumpagnu
- Italian: compagno, ⇒ compagna
- Sicilian: cumpagnu
North Italian:
- Istriot: cunpagno
- Romansch: compogn, compagn
Gallo-Romance:
- Old French: compaing (see there for further descendants)
  - French: copain, ⇒ compagne
Occitano-Romance:
- Catalan: company ⇒ companya
- Occitan: companh ⇒ companha
Ibero-Romance:
- Spanish: compaño (obsolete)

Via the accusative compāniōnem:

Italo-Romance:
- Italian: compagnone
- Sicilian: cumpagnuni
North Italian:
- Old Lombard: compagnon
- Old Venetan: compagnò
Gallo-Romance:
- Old French: compaignon (see there for further descendants)
  - French: compagnon
Occitano-Romance:
- Catalan: companyó
- Old Occitan: companhon, compalhó
Ibero-Romance:
- Old Galician-Portuguese: companhão
  - Northern Portugal: ⇒ companhões (testicles)
- Spanish: compañón