Quenya 

-ssë

at

-ssë (1) locative ending (compare the preposition se, "at", q.v.); in Lóriendessë, lúmessë, máriessë, yalúmessë (q.v. for reference); pl. -ssen in yassen, lúmissen, mahalmassen, símaryassen, tarmenissen, q.v. Pronouns take the simple ending -ssë, even if the pronoun is plural by its meaning (messë "on us", VT44:12). The part. pl. (-lissë or -lissen) and dual (-tsë) locative endings are known from the Plotz letter only.