keratosis pilaris; chicken skin
Medical term for a common, harmless skin condition causing small, rough bumps, often on the upper arms or thighs. Colloquially called 'chicken skin'.
Keratosis pilaris is a skin condition that causes small bumps on the arms or thighs.
Compound of 毛孔 (もうこう, 'pore') + 性 (せい, '-like, of that nature') + 苔癬 (たいせん, 'lichen'), a medical calque from Western terminology.