EL NINO

[El Ni.no] n, pl El Ninos [Sp, lit., the child (i.e., the Christ child); fr. the appearance of the flow at the Christmas season] (1925): an irregularly occurring flow of unusually warm surface water along the western coast of South America that is accompanied by abnormally high rainfall in usu. arid areas and that prevents upwelling of nutrient-rich cold deep water causing a decline in the regional fish population