The Gnomish Lexicon of the 1910s had G. bageth, first given as the equivalent of G. banc “trade” and then revised to mean “market” (GL/21). It was marked “pl.” indicating it was a plural word, and was clearly based on G. bag- “trade” (GL/21). Early Noldorin Word-lists of the 1920s had ᴱN. bagarth “market”, also based on ᴱN. bag- “trade” (PE13/138).

Neo-Sindarin: For purposes of Neo-Sindarin I would adapt these “market” words as ᴺS. bangath, an abstract noun based on the later verb [N.] banga- “trade”.