Linter or lint tool: The program called by the user, generally via command line or in CI. Configuration may or may not be provided as command line parameters.
Driver: The internal code that loads and executes various lints. Not the lints themselves.
Lint package or lint crate: A set of lints provided as a single library, whatever form that ultimately takes. Likely forms a namespace (such as foo::* for the foo crate).
Lint implementation: A dynamically loadable lint. Part of a lint package.
Lint group: A set of lints within a lint package that are related in some way. The grouping is defined by the lint package author.
End user or lint user: The person who calls the linter from the command line. Output is displayed to this user.