*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)