from Wiktionary, Creative Commons Attribution/Share-Alike License
- proper n. The brightest star in the southern constellation of Centaurus. Alpha Centauri is actually a binary star with Proxima Centauri as a third component. Alpha Centauri B is less bright than Alpha Centauri A and is somewhat less bright than our sun.
From α (brightest) + Centauri ("of the constellation Centaurus") (Wiktionary)