Middle Primitive Elvish
sed
root. rest
esek
root. *sedge, reed
ezdē
noun. rest
lisge
noun. reed
Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
A (Ilkorin-only?) root in The Etymologies of the 1930s with the derivatives Ilk. esg “sedge, reed”, Ilk. esgar “reed-bed”, and Ilk. Esgaroth “reed-lake” (Ety/ESEK). Elsewhere it seems S. lisg means “reed” as in S. Lisgardh “Land of Reeds” (UT/34), and similarly ᴹQ. liske < ᴹ✶lisge (PE19/51). Thus I suspect ᴹ√ESEK was a transient idea, one of the etymologies Tolkien considered for Esgaroth.