From the Plone book' s Navigation on a Plone Site chapter :

Contentmanagementsoftware.info

Navigation Tabs can be organized automatically basing on the folders that exist in the root of your Plone site

Tick the  box Automatically generate tabs and all the published folders that are there in the root will be displayed in Navigation tabs

If you remove that tick only one tab Home will be there:

You can customize navigation tabs the way you want. There is a possibility to add, remove tabs, change their order, but to fulfil any of these tasks you have to install a Quintagroup's product - Plone tabs to the site

To remove the home tab

Navigate to the ZMI via the site setup, then portal_actions -> portal_tabs

Then click on index_html (Home) and uncheck Visible? and [save changes]