Use of “marron”

Question

My dictionary shows both feminine and plural forms? Notes suggest that “marron”doesn’t change. Please explain.
Jan Gannon

Accepted Answer

The lesson is specifically about the use of 'marron' as an adjective for a colour - in this context it is invariable as stated. 
There are other meanings for 'marron' as a noun or adjective, and it can be variable in those contexts, although use in the feminine form is rare, according to Larousse.
 https://dictionnaire.lerobert.com/definition/marron 
https://www.larousse.fr/dictionnaires/francais/marron/49608

Answer

here is an easy answer for you (I hope!) Marron is a nut. Noisette is also a nut. They are nouns and used as adjectives for color. (from a French native teacher)

Answer

However, marron has meaning beyond just being a nut, or a colour. Hence the dictionary links.