Middle English word rein-drope comes from Proto-Germanic *drupô (A drop (of liquid).), Proto-Germanic *regną (Rain.)

Detailed word origin of rein-drope

Dictionary entry	Language	Definition
*drupô	Proto-Germanic (gem-pro)	A drop (of liquid).
*regną	Proto-Germanic (gem-pro)	Rain.
*regnadrupô	Proto-Germanic (gem-pro)	Raindrop.
reġndropa	Old English (ang)
regndropa	Old English (ang)	Raindrop.
reyn drope	Middle English (enm)

Words with the same origin as rein-drope