ETL stands for Extract, Transform, and Load, which are the three key processes involved in moving data from various sources into a centralized data warehouse. The extraction phase involves gathering data from different sources, such as databases, APIs, or flat files. Once the data is extracted, it undergoes transformation to clean, format, and enrich it, ensuring it meets the requirements of the target system. Finally, the transformed data is loaded into a data warehouse or another destination for analysis and reporting. ETL is crucial for organizations looking to consolidate their data for better decision-making and insights, enabling them to leverage their data effectively.