'arroyo' originates from Spanish, specifically the word 'arroyo', where it meant 'stream' or 'brook.'

'arroyo' entered English from Spanish (retaining the form 'arroyo') and was adopted into regional English usage in the Americas to name seasonal streams and dry gullies.

Initially it meant 'stream' or 'brook'; over time in English it came to refer especially to a dry gully or seasonal stream in arid regions.