Terminal is a program that can do almost anything you can think of completely without a graphic interface. Did you ever have an Apple ][? A regular Mac user has absolutely no need for Terminal. Using it can be risky because it rarely ever gives you a warning that what you are telling it to do may damage something. That small black box looks like what you might see on the Dock when Terminal is running.
Now, I'll look up this "Dashboard" thing and see if it has a way of removing stuff from it. I assume it is part of the Mac OS?
Finder Help has no info on "Dashboard". How do you open/run it? Can you show me a screen shot of part of its window?
BTW, open your System Prefs, click the Keyboard prefs and hen the "Shortcuts" tab. You should see two boxes with lists of things. The left-hand box should have an item called "Screenshots". Click that and in the right-hand box you will see a list of key combinations for various types of screenshots.
[rant]For some unknown reason, Apple does not allow us to make this window larger, so in that right-hand box, some labels are too long to see completely.
So, Apple designed a whole system to display compressed lines of text to allow you to read what you could have seen with a larger window
Just move your cursor over one of the 'clipped' lines and Apple's geniuses will display the complete line if a neat little elongated box.
I'm sure you already knew that, of course, because we Mac users have always known that moving the cursor around randomly is the "natural, intuitive" way of finding what you have never been told about.
[/rant] (Edited to fix code for font color)