Quenya 

-a

it is said

-r nominative plural ending regularly used on nouns ending in -a, -i, -, -o, -u, e.g. Ainur, Valar, tier. Occasionally it is added also to nouns ending in -ë (that normally take the ending -I in the pl.). This seems to regularly happen in the case of nouns in - (see #fintalë, mallë, tyellë), sometimes also otherwise (see Ingwë, wendë, essë #1). This plural ending was ("it is said") first used by the Noldor (PM:402).