Pressure is the ratio of Force to the Area over which
that force is distributed.
The S.I. unit of Pressure is the "PASCAL"
Pressure is a scalar quantity, it has no direction.
The physics equation for pressure,
When the area is small, a moderate force can create a very large pressure. This is why a sharp knife is good at cutting things: when you push the very small area of the sharp blade against something, it creates a really large pressure.
And so, atmospheric pressure is scalar quantity. It doesn't have any particular direction. For example, the atmospheric pressure is acting on you right now. Its pushing you from the left, from the right, from the up, and from the down. Its acting around your whole body. This necessarily means, you can't find a particular direction of the atmospheric pressure.