Definition of "furrow"

furrow

/ˈfʌɹoʊ/

noun
plural furrows
1. A trench cut in the soil, as when plowed in order to plant a crop.
2. Any trench, channel, or groove, as in wood or metal.
3. A deep wrinkle in the skin of the face, especially on the forehead.
verb
third-person singular simple present furrows, present participle furrowing, simple past and past participle furrowed
1. (transitive) To cut one or more grooves in (the ground, etc.).
  Quotations
  Morn in the white wake of the morning star / Came furrowing all the orient into gold.
  1847, Alfred Tennyson, “Part III”, in The Princess: A Medley, London: Edward Moxon, […], page 47
2. (transitive) To wrinkle.
3. (transitive) To pull one's brows or eyebrows together due to concentration, worry, etc.
4. (intransitive) to become furrowed
  Quotations
  If you were bold enough to ask Antonin Scalia questions, you had to be precise. Otherwise the bushy black brows would furrow, the chin would crumple and the pudgy, puckish body would start to rock, eager to get at you.
  2016 February 20, “Obituary: Antonin Scalia: Always Right”, in The Economist‎