(1):

(v. t.) A single cluster or group of plants growing close together, and having the earth heaped up about them; as, a hill of corn or potatoes.

(2):

(n.) A natural elevation of land, or a mass of earth rising above the common level of the surrounding land; an eminence less than a mountain.

(3):

(n.) The earth raised about the roots of a plant or cluster of plants. [U. S.] See Hill, v. t.

(4):

(v. t.) To surround with earth; to heap or draw earth around or upon; as, to hill corn.