a thickened and hardened part of the skin or soft tissue, especially in an area that has been subjected to friction 胼胝,老茧 ■(Medicine)the bony healing tissue which forms around the ends of broken bone (医)骨痂 ■(Botany)a hard formation of tissue, especially new tissue formed over a wound (植)愈伤组织;胼胝体
语源
mid 16th cent.: from Latin callus (more commonly callum) 'hardened skin'