THOR.  In Scandinavian mythology the son of the deity Iörd.  He was the great ruler of the elements of nature, and the protector of all the arts of life.  He fought against the great frost giants, and was the god of fire, of agriculture, and of the domestic hearth.  He was represented as a red-haired and red-bearded man, holding a ponderous hammer. (An Archaic Dictionary, Cooper, 1876).

... The god who gives his name to Thursday is the invisible somebody who causes the thunder.  The Anglo-Saxons called him quite plainly Thunor; and we may safely assume that, so long as the name remained in this transparently intelligible form, the legendary history of the god was very scanty.  When the Scandinavians contracted the word into Thor (Thôrr), the way was laid open for mythopœic fancy; and thus arose the well-known stories of the frolicsome giant Thor, who went about with his mighty hammer battering iron gates and shivering rocks in sunder, and whose eyes flashed fire as he laughed the awful laughter which shook the mountains and the sky.  As the most striking characteristic of Jupiter, in popular apprehension, was his wielding of the thunder, his identification with Thor requires no explanation.  The contraction of Thunresdæg into Thursday seems to have been produced by the influence of the Scandinavian Thórsdagr, as the shortened form does not appear in any Anglo-Saxon document earlier than the period of Danish rule in England. (Belgravia, Braddon, 1880)