Meaning

1. Someone who contains; something that contains.
2. An item in which objects, materials or data can be stored or transported.
3. A very large, typically metal, box used for transporting goods.
4. Someone who holds people in their seats or in a (reasonably) calm state.
5. A file format that can hold various types of data.
6. An abstract data type whose instances are collections of other objects.
7. Any user interface component that can hold further (child) components.
8. A web container.
9. A bundle consisting of operating system, application code and dependencies to be run sandboxed inside a virtualized environment; (by extension) the environment itself.