The El Nino Southern Oscillation (ENSO) is a phenomenon that affects the world's weather patterns. It is characterized by a warming of the Pacific Ocean, which can lead to changes in the atmospheric circulation, causing extreme weather conditions such as floods, droughts, and hurricanes. There are several synonyms of ENSO that can be used interchangeably such as the EL Nino phenomenon, Southern Oscillation, or ENSO cycle. Other terms like ENSO index, La Nina event, or Oceanic Nino Index (ONI) are also used to describe the ENSO. Scientists use these terms to study and predict the impacts of the ENSO on the environment, including its effects on agriculture, fisheries, and water resources.