| an extraordinary or unusual thing, person, or event; an exceptional example or instance. |
| an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle. |
| DeForest (dĭ-fôr'ĭst) Pronunciation Key
American electrical engineer and inventor who is known as "the father of radio." He patented more than 300 inventions, including the triode electron tube, which made it possible to amplify and detect radio waves. |
| deforestation (dē-fôr'ĭ-stā'shən) Pronunciation Key
The cutting down and removal of all or most of the trees in a forested area. Deforestation can erode soils, contribute to desertification and the pollution of waterways, and decrease biodiversity through the destruction of habitat. |
The process of destroying a forest and replacing it with something else. The term is used today to refer to the destruction of forests by human beings and their replacement by agricultural systems.
Note: Deforestation is considered to be a main contributor to the greenhouse effect.