Difference Between Global Dimension, Shortcut Dimension, and Dimension

People often get confused with this three different terminologies.
First of all keep aside different dimension terminology, just remember concept of Dimension.
So you know how to create dimension what is purpose of dimension & that all. So before shortcut dimension or global dimension, first it is normal dimension that we are defining on dimension page.
So all characteristics & usage of "Dimension" will be applicable for Global Dimension & Shortcut Dimension both.
We are defining Dimension as Global Dimension or Shortcut Dimension in General Ledger Setup.
Now lets see what is difference between them.

For more clarity see below screen captures.

Point 1:
I have defined two Global Dimensions "Department Code" & "Unit Code". Below Screen Shot is of Item ledger entry showing Global Dimension as a part of table fields.

Point 2:
Below Screen Shot is of Purchase Order showing Global Dimension & Shortcut Dimension in Purchase Line for data entry.

Point 3:
Below Screen Shot is of General Ledger Setup from which you can see defined Global Dimensions & Shortcut Dimension.
Also check that Global Dimensions are assigned as Shortcut Dimension 1 & 2 by default.

That's the funda of Dimension, Global Dimension, and Shortcut Dimension. Hope I am able to clear the idea a little bit, If you want to discuss it further, simply fire a mail to me with your questions (kapilpunvar@gmail.com).