A data warehouse is an integrated, subject-oriented repository that consolidates data from various sources to support business intelligence and analytics. It organizes data into a structured format optimized for querying and reporting, typically using techniques like star or snowflake schemas. Data is extracted, transformed, and loaded (ETL) from operational systems into the data warehouse, ensuring it is clean, consistent, and aligned with business needs. By centralizing data storage and providing powerful querying capabilities, data warehouses enable organizations to perform complex analyses, generate insights, and support decision-making processes. They are essential for handling large-scale data analytics and reporting tasks.