Genesis 3:14 And the LORD God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life: 15And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.

6119 `aqeb aw-kabe' or (feminine) hiqqbah {ik-keb-aw'}; from 6117; a heel (as protuberant); hence, a track; figuratively, the rear (of an army):--heel, (horse-)hoof, last, lier in wait (by mistake for 6120), (foot- )step.