Apache Spark is an open-source distributed computing system designed for big data processing and analytics. It provides an in-memory processing engine that is faster than traditional MapReduce frameworks. Spark supports various workloads, including batch processing, machine learning, and real-time streaming. It integrates with tools like Hadoop, Kafka, and Hive to build scalable data pipelines. Apache Spark is widely used for big data analytics in industries like e-commerce, finance, and telecommunications.