Definition of "forest"

forest

/ˈfɒɹ.ɪst/

noun
plural forests
1. A dense uncultivated tract of trees and undergrowth, larger than woods.
  Quotations
  Who after Archimagoes fowle defeat / Led her away into a foreſt wilde, / And turning wrathfull fyre to luſtfull heat, / With beaſtly ſin though her to haue defilde, / And made the vaſſal of his pleaſures vilde.
  1590, Edmund Spenser, “Book I, Canto VI”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie, stanza 3, page 76
  Since the mid-1980s, when Indonesia first began to clear its bountiful forests on an industrial scale in favour of lucrative palm-oil plantations, “haze” has become an almost annual occurrence in South-East Asia. The cheapest way to clear logged woodland is to burn it, producing an acrid cloud of foul white smoke that, carried by the wind, can cover hundreds, or even thousands, of square miles.
  2013 June 29, “Unspontaneous combustion”, in The Economist, volume 407, number 8842, page 29
2. Any dense collection or amount.
  Quotations
  Squealing and still propelled by the kick, the calf scrabbled through the forest of legs and into the open.
  1998, Katharine Payne, Silent Thunder: In the Presence of Elephants, page 59
3. (historical) A defined area of land set aside in England as royal hunting ground or for other privileged use; all such areas.
  Quotations
  Throughout the 1500s, the populace roiled over a constellation of grievances of which the forest emerged as a key focal point. The popular late Middle Ages fictional character Robin Hood, dressed in green to symbolize the forest, dodged fines for forest offenses and stole from the rich to give to the poor. But his appeal was painfully real and embodied the struggle over wood.
  2006, Edwin Black, chapter 2, in Internal Combustion‎
  [...] in places such as the Forest of Bowland there is hardly a tree in sight and much of the area is a vast tract of almost barren gritstone hills and peat moorland.
  2013, Alexander Tulloch, The Little Book of Lancashire, The History Press
4. (graph theory) A graph with no cycles; i.e., a graph made up of trees.
  Quotations
  Let H be a traversal of an undirected graph G = (X, U). For given H, the set U can be split into set of tree edges from the forest GH and the set of inverse edges that do not belong to this forest.
  2000, Victor N. Kasyanov, Vladimir A. Evstigneev, Graph Theory for Programmers: Algorithms for Processing Trees, Springer Science & Business Media, page 16
5. (computing, Microsoft Windows) A group of domains that are managed as a unit.
  Quotations
  Forests are considered the security boundary in Active Directory; by this we mean that if you need to definitively restrict access to a resource within a particular domain so that administrators from other domains do not have any access to it whatsoever, you need to implement a separate forest instead of using an additional domain within the current forest.
  2008, Laura E. Hunter, Robbie Allen, Active Directory Cookbook, O'Reilly Media, Inc., page 17
6. The colour forest green.
verb
third-person singular simple present forests, present participle foresting, simple past and past participle forested
1. (transitive) To cover an area with trees.
  Quotations
  From the view-point of national economy professor Fehér communicates to us most interesting facts, which he has established in an important question now of actuality : in the subject of foresting the Great Hungarian Plains.
  1937, Széchenyi Scientific Society, Report on the Work of the Széchenyi Scientific Society: Founded for the Promotion of Research in Natural Sciences in Hungary, Zeéchenyi Scientific Society, page 83