Apache Spark is an open-source parallel data processing framework that supports all major big data environments, enabling both batch and real-time analytics with enhanced speed and ease of use. It features resilient distributed datasets (RDDs) that allow for fault-tolerant data processing and in-memory computing, making it significantly faster than Hadoop MapReduce. Spark can be used with various programming languages and integrations, catering to a wide range of data sources and analytical tasks.