Each axis is like a number line. The three axis are perpendicular to each other. The point at which they intersect is called the point of origin. The point of origin is designated as 0,0,0, because it is located on the 0 point on all three axis. Now let's say that you want to define a point in space. You can do this by giving three numbers. The first one is the distance of the point from the origin in the X axis. The second one is the offset of the point from the point of origin along the Y axis, and the third on.
