DockerHub is an online repository service where developers and organizations can store, share, and distribute Docker container images. It acts as a central hub for containerized applications, allowing users to access pre-built images or publish their own. DockerHub supports both public and private repositories, enabling collaboration and secure image management. It also integrates with CI/CD pipelines, automates image builds, and provides vulnerability scanning features. Security best practices recommend verifying image sources and using official or trusted repositories to reduce risks of malicious or compromised containers in production environments.