Gorsedd: GOOR-seth (th as in leather)
Old Welsh: high mound
Modern Welsh: throne
Originally meaning a high mound, possibly artificial, usually of sacred importance, like the Gorsedd Arberth in the Mabinogion, which prefigures the Seige Perilous in the Grail legend, where tribes would meet.
Current meaning is a gathering of Bards in Wales. An eisteddfod (session) occurs at a gorsedd.