- A male given name.
From Middle High German rein, which also appears in reinkurni, reinifano (“tansy”), Modern German Rainfarn, for this plant’s growing as field mark, from Old High German rein (“wall, baulk, ridge”), from Proto-Germanic *rainō, cognate with Icelandic rein, Swedish ren, English rean (“ridge, furrow, gutter”), Lithuanian raivė̃ (“furrow”), Latvian rieva (“furrow”), Latin rīma (“slit”), all perhaps related to Proto-Indo-European *h₁reh₁- and the antecedents of Reihe, English row, as well as to reif, English ripe.
- "Rain" in: Wolfgang Pfeifer (ed.), Etymologisches Wörterbuch des Deutschen (2nd ed. 1993).