English

rainflow

From rain + flow.

A compound of rain + flow

Proto-Germanic *regną ‘rain’

Proto-West Germanic *regn ‘rain’

Old English reġn ‘rain’

Middle English reyn

English rain

Proto-Germanic *flōaną ‘to flow’

Proto-West Germanic *flōan ‘to flow’

Old English flōwan ‘to flow’

Middle English flowen

Middle English flowe

English flow

Today it means

noun A flow of rainwater.

Language periods are conventional ranges, not dates for this word.

Etymograph / rainflow