1. a corn; a callus
    • 右足にたこができている
    • I have a corn [callus] on my right foot.
    • 中指にペンだこができた
    • A callus has formed on my middle finger (from writing so much).
    • その事だったら耳にたこができるほど聞いた
    • I have heard about that so often that I'm sick of it.