Jquery Widget vs Jquery Plugin, Differences, When to use which?

What are the main differences between a Jquery Widget and a Jquery Plugin.

Mainly:

• What purposes do they serve
• Is one better than another or do they both have their place in the jquery world
• What is an example where I would want to use one over another
• What is an example if any where either would be a fine solution
• What is an example of a widely used widget and a widely used plugin

I've never heard of a jQuery widget. I imagine some people might use the term to describe a... widget... that has been made with jQuery. Certainly there are widgets in jQuery UI, for example. It's an odd question.

A widget is a widget (always includes a visual element, sometimes includes reusable functionality), and can be a subset of a plugin or a plugin in and of itself.

A plugin extends jQuery directly and may or may not have a visual component.