Container security refers to the practice of securing containerized applications and their infrastructure. Key components include build pipeline, container images, registries, host machines, runtimes, platforms/orchestrators, and applications. Risks associated with containers include out-of-the-box deployments not being secure by default and complex hardening processes. Best practices for securing containers involve using trusted base images, keeping images up to date, reducing the attack surface, limiting container privileges, implementing access controls, scanning images for vulnerabilities, implementing network security, monitoring container activity, and training your team.