Elastic Block Store (EBS) is an Amazon Web Services (AWS) storage service that provides persistent, high-performance block-level storage volumes for use with Amazon EC2 instances. EBS volumes are automatically replicated within their Availability Zone to protect against hardware failure, offering durability and high availability. Users can attach, detach, and resize EBS volumes without affecting data, making it ideal for applications requiring frequent updates and consistent, low-latency performance. EBS supports encryption, snapshots for backups, and various volume types optimized for throughput or IOPS, making it suitable for databases, file systems, and enterprise applications.