[NB The brief explanation given below has been drafted on the assumption that the reader is already familiar with the basic building-blocks used in Celtic topographical place-names (Chapter 1 of the Home menu), with the structure of compound place-names (Chapter 2) and with the structure of Celtic river-names (Chapter 19)]
This tribal name is apparently known only from the Geography of Ptolemy.
The Demet part of the tribal name Demetae is a straightforward inversion-type place-name element meaning ‘summit of hill high’. The name indicates that the Demetae used the hill-letter m. One sees this m in Maridunum, the hillfort on Merlin’s Hill, a little to the east of Carmarthen. Ptolemy assigns Maridunum to the Demetae. If this is correct then dunum must be the earliest element in the place-name, this being followed chronologically by the hill-letter r used in the inversion-type manner. Finally the hillfort was taken over by the Demetae, who applied their hill-letter m in the inversion-type manner.
Note that at least one manuscript of Ptolemy gives the form Demecetae. This form would also be in order, since Demecet simply means ‘summit of hill steep high’. This would be an earlier form, the ce being omitted to leave the better-known Demetae form.
[This page was last modified on 24 March 2021]