Definition from Wiktionary, the free dictionary
Alternative forms 
- (transitive) To make (something) as small or as insignificant as possible.
- (computing, transitive, graphical user interface) To remove (a window) from the main display area, collapsing it to an icon or caption.
- I didn't close anything, but I minimized all the windows so I could see the desktop.
To make small as possible
(computing) To cause a window to disappear