Hadoop is an open-source framework designed for storing and processing large datasets across clusters of computers. It allows for the distributed storage and analysis of data, making it easier to handle big data applications. The core components of Hadoop include the Hadoop Distributed File System (HDFS) for data storage and the MapReduce programming model for processing data. Hadoop is highly scalable, meaning it can grow with the needs of an organization by adding more machines to the cluster. It is widely used in various industries for tasks such as data analysis, machine learning, and data warehousing, enabling businesses to gain insights from vast amounts of information.