Definition of root directory in US English:

root directory

noun

Computing
  • The directory at the highest level of a hierarchy.

    • ‘If you want to block certain engines from certain files that do not reside in your root directory you simply need to point to the right directory and then list the file as normal.’
    • ‘This file should not be saved under the root directory for security reasons.’
    • ‘The installation program on the tested version doesn't yet support long path names, so installation essentially must be off the root directory.’
    • ‘To do this, go to the root directory of the source code and execute.’
    • ‘What can I do to make a user's directory be like a root directory, where the user just has an access to that directory or subdirectory?’

Pronunciation

root directory

/ˈrut dəˈrɛktəri/