Question

difference between pressure and stress?

Answer 1

Pressure basically is thrust per unit area. Here the thrust applied is external. Whereas in stress, is the average force per unit area. here the average force is the internal force the body applies as a reaction to an external force.

Answer 2

Pressure is knowing you have a big exam tomorrow that you need to study for.

Stress is what you have after you take the exam knowing that you didn't actually study :)

Answer 3

Here's a more correct answer:

Pressure is the external force acting over a unit surface area of a material. Stress is an internal force acting over a cross sectional area within the material. They both have the units of force per area which are typically noted in Pascals:
\[1 Pascal = \frac{1N}{m^2}\]