hackle

When referring to the tool used in textile production, the term is a technical piece of equipment. In this context, it describes a specific mechanical process of refining raw plant fibers to ensure they are parallel and free of debris before spinning.

When used to describe animal anatomy, the word is almost exclusively used in the plural form "hackles." The phrase "hackles rose" is a common idiomatic expression used to describe a state of sudden aggression, defensiveness, or intense agitation, mirroring the biological response of a dog's skin muscles contracting to make the hair stand upright.