Similar words
parceiro
parceiro is more general, a partner in any sense, romantic or business; sócio specifically means a business partner or shareholder.
Similar in other languages
German
Partner
Partner is the German word for the same thing — both mean "partner."
French
partenaire
partenaire is the French word for the same thing — both mean "partner."
Practice
1 What does sócio mean?
partner
2 Fill the gap: Meu ___ chegou.
Full sentence: Meu sócio chegou. (My partner arrived.)
3 Which fingerprint chart matches sócio?
sócio: neutral register, common frequency, general domain, neutral connotation.