We don't have synonyms for river tay yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are riverway, river rat and river cam.
(N) :
The River Tay (probably from the conjectured Brythonic Tausa, possibly meaning 'silent one' or 'strong one' or, simply, 'flowing' David Ross, Scottish Place-names, p. 209.
(N) :
The River Tay (probably from the conjectured Brythonic Tausa, possibly meaning 'silent one' or 'strong one' or, simply, 'flowing' David Ross, Scottish Place-names, p. 209.