Closed vs. Hidden Web Part - what is the difference?

Question

What is the difference between "Hidden Web Part" and "Closed Web Pat"?

PS.
I tried to search on the internet but could only find "deleting vs. closing" web parts

Sharepoint 2010 (Sharepoint Designer 2010)

Update (due to one of confusing answers to this question):
The quote from [1. p.119]:

Tip Closed Web Parts can increase the time it takes for a browser to load the page. Keep the number of closed Web Parts to a minimum and only close a Web Part when you want to temporarily hide a Web Part and its customizations. In the browser, you can find closed Web Parts by first placing a page in edit mode. Then, on the Editing Tools, Insert tab on the server ribbon, click Web Part, and under Categories, click Closed Web Parts. The Closed Web Parts category appears only if the page contains closed Web Parts.

Cited:
[1]
Penelope Coventry
Microsoft® SharePoint® Designer 2010 Step by Step.
O’Reilly Media, Inc.

Answer 1

Closed Webpart > When you close a webpart , it goes and stays in the closed webpart gallery. You can see this gallery when you click on Edit Page on the 2010 ribbon > Insert > Webpart > Closed Webpart Gallery.

When you close a webpart it does not get loaded in the webpage during realtime. The closed webparts even then reside in this gallery which can be reused anytime in the future.

Hidden Webpart > These webparts can be deployed through visual studio and can be loaded in the page during realtime however wont appear to the user in the webbrowser.

Answer 2

On a simple definition, I would say that an hidden webpart is still loaded in the webpage, a closed one no.