El Ni·ño 
(nēnyō)
(nēnyō)n.
A climatic event occurring every two to seven years, characterized by warming of surface waters and reduced upwelling of cold, nutrient-rich water off the western coast of South America, causing die-offs of plankton and fish and influencing jet stream winds, altering storm tracks and affecting the climate over much of the world.
[American Spanish (originally used by fisherman in Ecuador and Peru as a name for the warm ocean current typically appearing around Christmastime in El Niño years), from Spanish, the Christ child : el, the (from Latin ille; see al-1 in the Appendix of Indo-European roots) + niño, child (from Old Spanish ninno, from Vulgar Latin *nīnnus).]
El Niñotop: normal water temperatures, with warm water concentrated in the western tropical Pacific
bottom: El Niño conditions, with warm water extending from the western tropical Pacific to the eastern Pacific