Lugudunon
1 Celtic place name “fort of Lugus”
This is the basis of the present-day place names in Continental Europe, via the Latin form Lugudunum / Lugdunum:
(1) Lyons (south-eastern France) (2) Laon (3) Loudon (4) Laudun (5) Montlezun (6) Montlauzun (7) Leiden
In Wales there is an example with the elements reversed – Dinas Dinlleu ‘hillfort of Dinlleu’ (locally pronounced Dinas Dinlla).
Dinlleu = Celtic dun- (= fort) + Lug- (= Lugus, name of a God)