noun

• (historical) A defined area of land set aside in England as royal hunting ground or for other privileged use; all such areas.
  "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."
• (graph theory) A graph with no cycles; i.e., a graph made up of trees.
  "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 G_H and the set of inverse edges that do not belong to this forest."
• (computing, Microsoft Windows) A group of domains that are managed as a unit.
  "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."
• (uncountable) The color forest green.

verb

• (transitive) To cover an area with trees.
  "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."

name

• (soccer) Nottingham Forest F.C.