The word was changed to beren in the Etymologies, but meren would be restored together with mereth
Noldorin
bereth
noun. feast, festival
bereth
noun. queen
bereth
noun. queen, spouse
mereth
noun. feast, festival
brethil
noun. beech
brethel
noun. beech
brethel
noun. beech, beech-tree, silver birch
elbereth
feminine name. Queen of Stars, (lit.) Star Queen
fêr
noun. beech-tree
meren
adjective. festive, gay, joyous
rhîs
noun. queen
rhîs
noun. queen
The word was changed to bereth in the Etymologies, but was never changed in the texts (cf. Mereth Aderthad and the compound Merethrond)