Alpha Centauri is the nearest star system. Its a binary star
system of Alpha Centauri A and Alpha Centauri B. If someone asks
you what is the nearest star ? then the answer will be "proxima
centauri" in my opinion.
nearest star: proxima centauri
nearest star system: Alpha centauri A and B.
Some people believe that its a triple star system of Prixma,
Alpha A and Alpha B. centauri.