I had asked this question before and received terriffic responses and realized many had the same lack of understanding of what these terms mean that I did. I want to say GiantJason and Painter gave great insight.
Did you mean 1 gap VS 2 gap?
Yes, all of the above.
To be frank Bama, I think you are getting gap and technique confused. I have never heard of a 3 gap, but I have heard of a 3 technique lineman. Now Gaps are the area between offensive men on the line. They are lettered and here is a standard diagram
(http://www.footballoutsiders.com/images/DLINE2.jpg)
There are two different options of defensive line play, one gap or two gap. I will go into detail later.
Now there is also designations as to where a d-linemen (or linebacker for that matter) lines up. They are designated by numbers. Here is the diagram for that.
(http://www.footballoutsiders.com/images/DLINE1.jpg)
A 3 technique lineman lines up on the guard