Quenya 

nendil

noun. beast that lives in the water

A general term for aquatic animals, including fish (lingwi) as well as other species such as whales and dolphins (NM/336). It appears to be a combination of nén “water” and -(n)dil “-lover”.

Elements

WordGloss
nén“water, water, [ᴱQ.] river”
-(n)dil“-friend, -lover; devotion, disinterested love”

Nendili

water-lovers

Nendili noun "Water-lovers", the most frequently used "title" or secondary name of the Lindar (Teleri) (WJ:411) Sg. #Nendil.