-to ending for dual genitive (Plotz)
-o (1) genitive ending, as in Altariello, Oromëo, Elenna-nórëo, Rithil-Anamo, Rúmilo, Lestanórëo, neldëo, omentielvo, sindiëo, Valinórëo, veryanwesto, q.v. In words ending in -a, the genitive ending replaces this final vowel, hence atto, Ráno, Vardo, vorondo as the genitive forms of atta, Rána, Varda, voronda (q.v.) Following a noun in -ië, the ending can have the longer form -no, e.g. *máriéno "of goodness" (PE17:59, but contrast sindiëo "of greyness" in PE17:72). Where the word ends in -o already, the genitive is not distinct in form, e.g. ciryamo (q.v.) = "mariner" or "mariners". Pl. -ion and -ron, q.v.; dual -to (but possibly -uo in the case of nouns that have nominative dual forms in -u rather than -t). The Quenya genitive describes source, origin or former ownership rather than current ownership (which is rather covered by the possessive-adjectival case in -va). The ending -o may also take on an ablativic sense, "from", as in Oiolossëo "from (Mount) Oiolossë" (Nam), sio "hence" (VT49:18). In some of Tolkiens earlier material, the genitive ending was -n rather than -o, cf. such a revision as Yénië Valinóren "Annals of Valinor" becoming Yénië Valinórëo (MR:200).
Soronto (þ?), masc. name, seems to incorporate soron "eagle"; the ending -to is rare (occurs in suhto, q.v.), here apparently used to derive a masculine name.
sor, sornë noun "eagle" (LT1:266); rather soron in LotR-style Quenya
attat2 fathers or neighbours
-t (1) dual ending, on nouns denoting a _pair of something: attat "2 fathers or neighbours" (VT48:19; see _atto), máryat "her (pair of) hands" (Nam), siryat "two rivers" (VT47:11), ciriat "2 ships" (Letters:427 read ciryat as in the Plotz Letter?), maquat "group of ten" (from maqua, meaning among other things "group of five") (VT47:7), nápat "thumb and index as a pair" (VT48:5), also compare met "us two" as the dual form of me "us" (Nam, VT47:11). Other dual endings known from the Plotz letter: genitive -to, possessive -twa, dative -nt, locative -tsë, allative -nta, ablative -lto, instrumental -nten, plus -tes as a possible short locative. It may be that these endings only apply to nouns that would have nominative dual forms in -t, and that nouns preferring the alternative dual ending -u would simply add the otherwise "singular" case endings to this vowel, e.g. *Alduo rather than ?Alduto as the genitive form of "Two Trees" (Aldu). The ending -t is also used as a verbal inflection, corresponding to pl. -r (elen atta siluvat**, "two stars shall shine", VT49:45; the verb carit** "do" would also be used with a dual subject, VT49:16; cf. also the endings listed in VT49:48, 50).
sorno (þ) noun "eagle" (archaic thorno) _(Letters:427). Also soron. Early "Qenya" has sor, sornë (LT1:266)_
soron (or sornë) (þ) noun "eagle", before an ending sorn- as in pl. sorni, "gen.sg....sornen"; in LotR-style Quenya this would be the dative singular instead (THOR/THORON). SD:290 has the pl.soroni "eagles", changed to sorni as in the Etymologies. Early "Qenya" has the forms sor, sornë (LT1:266)
Soronúmë (prob. þ) (name of a constellation, apparently incorporating soron "eagle") (SA:thoron)
ëa (3) "eagle" (LT1:251, LT2:338), a "Qenya" word apparently superseded by soron, sornë in Tolkien's later forms of Quenya.
ëaren noun "eagle" or "eyrie" (LT1:251; this early "Qenya" word is evidently no more valid than ëa "eagle" in LotR-style Quenya.)