Naming convention: argument vs option

What is the standard name for an argument in coreutils?

GNU coreutils uses:

• 'option' for the named arguments
• 'argument' for the value of an 'option'
• 'operand' for arguments, which are not an option, typically file names

uutils uses:

• generally 'option' for the named arguments
• argument for the operands (see ls --help)
• no known name for named option arguments

This here seem wrong in any case:
When I look at the clap error messages, the word argument is used instead:

Common clap error messages

clap-error-unexpected-argument = { $error_word }: unexpected argument '{ $arg }' found
clap-error-unexpected-argument-simple = unexpected argument
clap-error-similar-argument = { $tip_word }: a similar argument exists: '{ $suggestion }'
clap-error-pass-as-value = { $tip_word }: to pass '{ $arg }' as a value, use '{ $tip_command }'
clap-error-invalid-value = { $error_word }: invalid value '{ $value }' for '{ $option }'
clap-error-value-required = { $error_word }: a value is required for '{ $option }' but none was supplied
clap-error-missing-required-arguments = { $error_word }: the following required arguments were not provided:
clap-error-possible-values = possible values
clap-error-help-suggestion = For more information, try '{ $command } --help'.

In my humble opinion, these should be changed to "option", so it matches GNU outcome: "unexpected option xxx found".

Start by locating the clap error-message localization strings listed in the issue and review how coreutils distinguishes options, arguments, and operands. Check the surrounding terminology and existing tests, then update only the inconsistent wording if the project’s convention is confirmed and verify the affected CLI error output.