English
grainfall
From grain + fall.
Proto-Indo-European *ǵerh₂- ‘to grow old, to mature’
…
Proto-Italic *grānom
Latin grānum ‘seed’
Old French grain
Middle English greyn ‘a grain’
English grain
Proto-Indo-European *h₃elh₁- ‘to collapse’
Proto-Germanic *fallaną ‘to fall’
Proto-West Germanic *fallan ‘to fall’
Old English feallan ‘to fall’
Middle English fallen ‘to fall’
English fall
Today it means
noun The accumulation of (typically sand) grains to form a dune
Language periods are conventional ranges, not dates for this word.
Etymograph / grainfall