#Joomla Multi-Sites Yes, it is possible to use 1 single installation of Joomla files to run 2 or more different sites. This is the so called multi-sites scenario.
There are extensions the provide this possibility, but it is also possible with the core. Each option has its own pros and cons and possibilities.
Under certain scenarios, it's also possible to share database data (e.g. articles, or single sign-on for users among the shared sites).
The following resources will help you with your research:
##Joomla Docs
##Extensions