A monsoon is a seasonal prevailing wind which lasts for several months and has lasting climatic effects. It refers to both the wet monsoon, or rainy season, and the dry monsoon experienced periodically in the South East Asian continent. The term was first used in English with this meaning in India, Bangladesh, Pakistan and neighboring countries to mean the seasonal winds blowing from the Indian Ocean and Arabian Sea in the southwest bringing heavy rainfall to the region. In hydrology, monsoonal rainfall is considered to be that which occurs in any region that receives the majority of its rain during a particular season, and so monsoons are referred to in relation to other regions such as in North America, Sub-Saharan Africa, Brazil and East Asia.
The English name Monsoon, was derived from the Hindi word mausam meaning 'weather' in the time of the British Empire.
In terms of total precipitation, total area covered and the total number of people affected, the monsoons affecting the Indian Subcontinent dwarf the North American monsoon (also called the "Mexican", "southwest", "desert", or "Arizona" monsoon).