From Middle High German regenboge, from Old High German reganbogo, from Proto-Germanic *regnabugô. Analysable as Rään (“rain”) + Boge (“bow”). The -n- of the first component was lost early on (at a stage when such loss was restricted to positions before non-alveolar consonants, as it still is in Luxembourgish). Therefore, the word did not undergo the later contraction from *Räjen to Rään.
Räjeboge m (plural Räjeboge)