Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750–2000 mm (68–78 inches). The monsoon trough, alternatively known as the intertropical convergence zone, plays a significant role in creating the climatic conditions necessary for the Earth's tropical rainforests.
Around 40% to 75% of all biotic species are indigenous to the rainforests. It has been estimated that there may be many millions of species of plants, insects and microorganisms still undiscovered in tropical rainforests. Tropical rainforests have been called the "jewels of the Earth" and the "world's largest pharmacy", because over one quarter of natural medicines have been discovered there. Rainforests are also responsible for 28% of the world's oxygen turnover, sometimes misnamed oxygen production, processing it through photosynthesis from carbon dioxide and consuming it through respiration.
The undergrowth in some areas of a rainforest can be restricted by poor penetration of sunlight to ground level. If the leaf canopy is destroyed or thinned, the ground beneath is soon colonized by a dense, tangled growth of vines, shrubs and small trees, called a jungle. There are two types of rainforest, tropical rainforest and temperate rainforest.
The term Banyumasan is also used as an adjective referring to the culture, language and peoples of a wider Banyumas area, equivalent to the pre-independence Banyumas Residency. The language of Banyumasan are of Austronesian origin, and is usually considered to be a dialect of Javanese.