Réveillon vs Nöel

Réveillon is used for both - if you are lucky enough to be in France at that time, you will certainly hear it used for Christmas Eve’s celebration with its long dinner culminating in present opening immediately after midnight, and for the equally or even more prolonged New Year’s Eve conviviality.  

https://www.larousse.fr/dictionnaires/francais/réveillon/69069

https://www.wordreference.com/fren/réveillon

Isn't Noel for Chrismas?

Daniel, yes ‘Noël’ translates generally to the English use of “Christmas”,  but the question asked here previously was about the meaning and use of  ‘Réveillon’. 

It might be better to post a new question separately if you are after more information, as old threads are less likely to attract responses.