English
hillstream
From hill + stream.
Proto-Indo-European *kl̥Hnís ‘top, hill, rock’
Proto-Germanic *hulliz ‘hill’
Proto-West Germanic *hulli ‘hill’
Old English hyll ‘hill’
Middle English hil ‘hill’
English hill
Proto-Indo-European *srew- ‘to flow’
…
Proto-Germanic *straumaz
Proto-West Germanic *straum
Old English strēam
Middle English streem
English stream
Today it means
noun A swiftly-flowing stream, typically one that runs down a hillside
Language periods are conventional ranges, not dates for this word.
Etymograph / hillstream