Container
In plain terms
A lightweight, portable package of an app plus everything it needs to run.
Going deeper
Containers bundle code, libraries, and config so the app runs identically on a laptop, a server, or the cloud, sharing the host OS kernel rather than booting a full virtual machine. This makes them fast to start and easy to ship consistently.
Under the hood
Built on Linux namespaces (isolation) and cgroups (resource limits); immutable and ephemeral by design, with state externalized to volumes or services.
Examples
Docker containers, containerd, Podman, OCI images, Kubernetes pods.
Think of it like...
Like a food truck versus a full restaurant: it carries its own kitchen and supplies, so it works the same wherever you park it, without rebuilding the building.