Segodunum

Segodūnum is an old Celtic place name derived from Proto-Celtic *sego-dūno-, meaning "strong fortress".

It can refer to the following locations:
 * Rodez, Aveyron, former town of the Ruteni in Aquitania
 * Segedunum, Wallsend, England.
 * Suin, Saône-et-Loire
 * Syon Haute-Savoie
 * Würzburg, Bavaria

It may have Germanic counterparts in Swedish Fornsigtuna and Sigtuna, from Proto-Germanic *siga-tūna-, Old Norse Sigtún.