callus; corns (on the feet)

callus (patch or hardened skin); corns (on the feet)

feet with calluses; fig. a long and hard march

thick callus

Wu Jianren (1867-1910), late Qing dynasty novelist, author of The strange state of the world witnessed over 20 years 二十年目睹之怪現狀|二十年目睹之怪现状