n. A long, narrow, shallow trench made in the ground by a plow.n. A rut, groove, or narrow depression: snow drifting in furrows. n. A deep wrinkle in the skin, as on the forehead.v. To make long, narrow, shallow trenches in; plow.v. To form grooves or deep wrinkles in.verb-intransitive. To become furrowed or wrinkled.