container
also: Docker container, OCI container
A lightweight, isolated runtime environment that bundles an application with its dependencies, libraries, and configuration into a single package that runs consistently across different systems.
A container is a standardized unit of software that encapsulates an application and everything needed to run it—including the runtime, libraries, and system tools—without requiring a full virtual machine. Containers use operating system-level virtualization to create isolated processes that share the host kernel while maintaining separation from other containers and the host system.
Containers are typically created from images, which are read-only templates defining the container's contents. Popular container technologies include Docker and Podman. For example, a web application container might include a Python runtime, Flask framework, and database driver—all packaged so it runs identically whether deployed on a developer's laptop, a test server, or production cloud infrastructure.
Containers are more lightweight and faster to start than virtual machines because they don't need their own kernel. Multiple containers on the same host can be managed together using orchestration platforms like Kubernetes, which handle scaling, networking, and lifecycle management across clusters.