bayonet hair

bay·o·net hair

a spindle-shaped developmental defect occurring at the tapered end of the hair.
A developmental defect of the hairshaft with excess keratinization of the upper third, which is common in ichthyosis and seborrhea and may be seen in normal scalps

bay·o·net hair

(bā-ŏ-net' hār) A spindle-shaped developmental defect occurring at the tapered end of a hair.