A jungle is land covered with dense vegetation dominated by trees. Application of the term has varied greatly during the last several centuries. Prior to the 1970s, tropical rainforests were generally referred to as jungles but this terminology has fallen out of usage. Jungles in Western literature can represent a less civilised or unruly space outside the control of civilisation: attributed to the jungle's association in colonial discourse with places colonised by Europeans.
The word jungle originates from the Sanskrit word jangala (Sanskrit: जङ्गल), meaning uncultivated land . Although the Sanskrit word refers to dry land, it has been suggested that an Anglo-Indian interpretation led to its connotation as a dense "tangled thicket" while others have argued that a cognate word in Urdu did refer to forests. The term is prevalent in many languages of the Indian subcontinent, and the Iranian Plateau, where it is commonly used to refer to the plant growth replacing primeval forest or to the unkempt tropical vegetation that takes over abandoned areas.
Because jungles occur on all inhabited landmasses and may incorporate numerous vegetation and land types, the wildlife of jungles can not be defined and consists of the biota of the constitute land type and region.
One of the most common meanings of jungle is land overgrown with tangled vegetation at ground level, especially in the tropics. Typically such vegetation is sufficiently dense to hinder movement by humans, requiring that travellers cut their way through. This definition draws a distinction between rainforest and jungle, since the understorey of rainforests is typically open of vegetation due to a lack of sunlight, and hence relatively easy to traverse. Jungles may exist within, or at the borders of, rainforests in areas where rainforest has been opened through natural disturbance such as hurricanes, or through human activity such as logging. The successional vegetation that springs up following such disturbance of rainforest is dense and impenetrable and is a ‘typical’ jungle. Jungle also typically forms along rainforest margins such as stream banks, once again due to the greater available light at ground level.