ETYM Malay műsim, from Arabic mausim a time, season: cf. French monson, mousson, Sr. monzon, Portu. monçăo, Italian monsone.
1. A seasonal wind in southern Asia; blows from the southwest (bringing rain) in summer and from the northeast in winter.
2. Any wind that changes direction with the seasons.
3. Season in southern Asia when the southwestern monsoon blows, bringing heavy rains.
Wind pattern that brings seasonally heavy rain to S Asia; it blows toward the sea in winter and toward the land in summer. The monsoon may cause destructive flooding all over India and se Asia from April to Sept, leaving thousands of people homeless each year.
The monsoon cycle is believed to have started about 12 million years ago with the uplift of the Himalayas.