Meaning & History
The meaning and origin of the first element is rather uncertain: we know that it comes from gis (the original form was possibly gîs), but we don't exactly know where gis itself comes from. But there are a few possibilities. It might come from Gallo-Celtic gaiso "spear" (see GAISERIC) or it might be a short form of gisel, which means "hostage" or "pledge" (see GISELLE). The second element in the name comes from Gothic valdan "to reign."