That should give you some idea of what Oracle is and its requirements. Oracle is currently the developer of VirtualBox which is virtual software. (Like Parallels and Fusion)
Oracle's a company with tons of products like Microsoft, Google or Apple. BTW Oracle is usually associated with databases (they started as a database company).
So, when someone says: "We use Oracle". It usually means that they use Oracle database systems and its associated products (RAC, Solaris, ecc)