Where does “Sommersonnenwende” come from?
Sommersonnenwende (German) comes from German Sommer, from Middle High German sumer, from Old High German sumar, from Proto-West Germanic sumar, from Proto-Germanic sumaraz, from Proto-Indo-European sm̥m-aro-, from Proto-Indo-European sm̥-h₂-ó-, from Proto-Indo-European semh₂- — summer, year.
Sommersonnenwende (German): summer solstice
Ancestry of “Sommersonnenwende”, step by step