Basically, a content management system is a web based system that manages YOUR website content.

What is Content?

Content is in essence, any type or 'unit' of digital information. It can be text, images, graphics, video, sound, documents, records etc - or in other words - anything that is likely to be managed in an electronic format.

What is Content Management?

Content Management is effectively the management of the content described above, by combining rules, process and/or workflows in such a way that its electronic storage is deemed to be 'managed' rather than 'un-managed'.

What is the CM System?

The system itself is definable as a tool or combination or tools that facilitate the efficient and effective production of the desired 'output' using the managed content.

To combine all three, we can say:

"A CMS is a tool that enables anyone to create, edit, manage and publish a variety of content (such as text, graphics, video, documents etc), whilst being constrained by a centralised set of rules, process and workflows that ensure coherent, validated electronic content."