Morphology: from “traeth” or possibly “traethu”
Phonetic: dry-then
Though the word "traeth" meaning a beach, is more commonly used for the seaside, this is possibly an example of the use of the word in the context of an area on the banks of a river such as a marsh or bog. Another theory could be that "traeth" here comes from "traethu" – "to speak out", possibly a description of the babbling noise of the river. There are records of the name dating back to 1465, where it was shown as Trayth Maghon and the current version of the name first appeared in the form Melin-y-Draythen in 1615.