That’s for custom template files to help display your taxonomy data. They’d be php files you add to your active theme.
If you have a term of “foobar” from the “gulf” taxonomy, then taxonomy-gulf-foobar.php
would be loaded when viewing the archive for the “foobar” term.
taxonomy-gulf.php
will be loaded for all terms from “gulf” if a file matching above isn’t available.
taxonomy.php
will be loaded for all terms, regardless of taxonomy slug, if either of the above isn’t available.
and so on down the template hierarchy chain.
This information isn’t going to be used for doing a query of all the terms for the taxonomy and doing something with them.