There are multiple origins and meanings for the name Thor:
1. Scandinavian (Danish, Swedish and Norwegian) name-giving meaning - "thunder, lightning".
Thor is a Scandinavian (Þórr) hammer-wielding God associated with thunder, lightning, storms, oak trees, strength, destruction, fertility, healing, and the protection of mankind. The cognate deity in wider Germanic mythology was known in Old English as Þunor and in Old High German Donar.
2. See the name Tor