Sundown comes from English sun and down, where down derives from Old English dūn, Proto-Celtic dūnom, and ultimately Proto-Indo-European roots related to height and position.
sundown (English): Sunset; A hat with a wide brim to shade the eyes...
Definitions
Sunset; A hat with a wide brim to shade the eyes...
Ancestry of “sundown”, step by step
sundown traces back through two separate lines of ancestry.