1. A barb or filament from the shaft of a feather, used in fly-tying for fishing lures.
Usage: fishing/angling term; often used in the plural

Examples

• The fly tier carefully selected herls from a peacock feather for the nymph pattern.
• He wrapped the herl around the hook shank to create the body of the artificial fly.
• Quality herls are essential for tying realistic-looking fishing flies.
• The angler used ostrich herls to add bulk and movement to his streamer pattern.