hills is a form of:

Hill



noun
1.
(A natural raised part of the earth's surface, a small heap, a natural elevation of land, a small mountain, a mound. -over the hill past the peak of rosperity or effectiveness) climb a hill ភ្នំ (តូចៗ)
Example: A distant hill, a hill of beans.hill of ants ដំបូក, hill of potatoes រង (ដំឡូង ត្រាវ ។ល។)
verbpast tense: hilled ; past participle: hilled ; present participle: hilling ;
1.
(TRANSITIVE) (to heap up) hill (up) ពូន
ENGLISH MEANING
noun
1.
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.
2.
The earth raised about the roots of a plant or cluster of plants. [U. S.]
3.
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.
verbpast tense: hilled ; past participle: hilled ; present participle: hilling ;
1.
(TRANSITIVE) To surround with earth; to heap or draw earth around or upon; as, to hill corn.