Spark is an open-source distributed computing system designed for big data processing. It allows users to perform data analysis quickly by utilizing in-memory computing, which speeds up data retrieval and processing compared to traditional disk-based systems. Spark supports various programming languages, including Python, Java, and Scala, making it accessible to a wide range of developers. Spark can handle large-scale data processing tasks and is often used in conjunction with other big data tools like Hadoop. It provides a unified framework for batch processing, stream processing, and machine learning, enabling organizations to analyze and derive insights from their data efficiently.