fen (feng-) noun "reed" (QL:38, stem feng- also in GL:34).
Quenya
Silmarien
-riën
fen
reed
liscë
reed, sedge
liscë _("k")_noun "reed, sedge" (LT2:335)
Sindarin
lisg
noun. reed, reed, [G.] sedge
A word appearing as an element in the name Lisgardh “Land of Reeds” (UT/34).
Conceptual Development: An earlier version of this name was G. Arlisgion or Garlisgion “Place of Reeds” (LT2/153; GL/67), which contained G. lisg or lisc “reed, sedge” from the Gnomish Lexicon of the 1910s (GL/54). This became ᴱN. lhesg “sedge” in Early Noldorin Word-lists of the 1920s (PE13/148).
lisc
reed
lisc, no distinct pl. form.
lisc
reed
no distinct pl. form.****
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!
Early Quenya
fen
noun. reed
Qenya
liske
noun. reed, reed, [ᴱQ.] sedge
A word mentioned in the Outline of Phonetic Development (OP1) of the 1940s, with the gloss “reed” and derived from primitive ᴹ✶lisge (PE19/51).
Conceptual Development: The word/root ᴱQ. LISKE “sedge, reeds” appeared in the Qenya Lexicon of the 1910s (QL/55). In the contemporaneous Name-list to the Fall of Gondolin, [ᴱQ.] liske was given as a cognate to G. lisg “reed” (PE15/28).
rí
noun. reed, grass-stem
A word appearing in the Declension of Nouns (DN) of the early 1930s glossed “grass-stem, reed” and derived from the root ᴹ√RĪI̯ as an example of a monosyllabic vocalic noun (PE21/38). In drafts of this section it was glossed only “reed” (PE21/41 note #147).
Middle Primitive Elvish
lisge
noun. reed
Silmarien (sometimes "-riën") fem. name, apparently incorporates sil(i)ma (Appendix A) and the feminine ending -ien, or -rien as a variant of -riel (garlanded maiden) as in Altariel (Galadriel).