Installing the JomSocial for the first time, will add set of several new menu items so you don't have to think about creating them one by one.
Due the nature of Joomla! menus being required to have an alias beside other required information, for easier finding we gave the name to this alias by the component name.
The outcome is, that the browser address bar will display simething like this when you visit JomSocial pages
How to change it
Since this is just an alias of the menu item, naturally, you will need to do the edits in the Joomla Menu Manager
Go to the Main Menu and search for "jomsocial"
Edit the name and alias, and you're all set.