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!
ost
noun. enclosure, yard; town
ost
noun. summer
ost
pronoun. yourselves
ostril
feminine name. Ostril
osta-
verb. to surround with walls, build up; to fortify, protect; to surround
ostor
noun. enclosure, circuit of walls
A noun appearing as G. ostor “enclosure, circuit of walls” in the Gnomish Lexicon of the 1910s, an elaboration of G. ost “enclosure, yard; town” (GL/63).
Neo-Sindarin: Since S. ost “citadel, (fortified) town” continued to appear in later Sindarin, I think this word might be retained as ᴺS. ostor “enclosure, circuit of walls, ✱town wall” for purposes of Neo-Sindarin.
ostrin an ost
place name. City of Seven Names
belegost
place name. *Great City
aust
noun. summer
barwen
noun. homestead
baur
noun. house
safwen
noun. summer
A verb appearing as G. osta- “to surround with walls, build up; fortify, protect; surround” in the Gnomish Lexicon (GL/63), based on the early root ᴱ√OSO as suggested by Christopher Tolkien (LT2A/Belegost; QL/s71).
Neo-Sindarin: Since ᴹ√OS “round, about” appears in Tolkien’s later writings, I would retain ᴺS. osta- for purposes of Neo-Sindarin, originally with the sense “to surround”, later more specifically “surround with walls” and by extension “fortify, protect”, probably due to the influence ost “(fortified) town”.