One of my friend has named his house as Mahavishnu Mitra

Answer: Mitra in sanskrit stand for Friend. Friend of Sri Mahavishnu !  Clever, indeed, he makes every other friends of Sri Mahavishnu as his friends 🙂 (Sri Mahavishnu in the Krishna Avathara has had umpreen friends; no one calls Him as Prabhu(o), or Lord, but all calling him as Krishna or Kanna. One such close friend of Sri Krishna was Kuchela!)