Wynn and Sigel are the names of two runes from an alphabet - the Futhark - used for the writing of German languages from the 2nd century AD. Only two groups of Indo-European languages have rune: Celtic languages and Germanic languages. In both cases, the word rune means "secret, mystery, wisdom, incantation" or "initiate". As they are used in the art of divination, each rune has a very specific meaning. Initially, the Futhark had 24 runes and has evolved over centuries.
The oldest attested inscriptions were found in Denmark, engraved in wood. First used by the Nordic Germans (Norwegians, Swedes, Danes), the alphabet was then used by the Anglo-Saxons who settled on the island of Brittany in the 5th century AD. But the very origins of the Futhark are still obscure. Some scholars claim that this alphabet comes from Greek or Latin. Others, more esoteric, argue that Old Futhark could have much more ancient origins in connection, not with the Mediterranean writings, but with the petroglyphs (symbolic drawings of rock art) of Hallristinger. Wynn and Sigel are runes of the Anglo-Saxon Futhark. They correspond, in Old Futhark, to Wunjo and Sowilo.
Whatever the alphabet used, the meaning of the runes is the same: Wynn means Joy and Sigel means Sun.