The french term for a quility beyond XO is Hors d'âge - Beyond Age.
The current law of France governs this grade as one of the XO's equal . However manufacturers will refer to this term as a grade beyond the XO.
Despite such reference, you will seldom see this grade being written on cognacs beyond XO. Instead, you will see the word "extra" without the word XO on the bottles. When you see this, you should recognise the cognac as one above the XO quality.
Coincidentally, manufacturers that produces top-of-the-line cognacs does not write any grading on their bottles other than the unique name of the production.
