What are the difference between stress and pressure ?

1. Stress-It is the internal force applied by the object to resist the deformation of their parts where as the pressure is external force applied on the object to deform the object parts.
2. In another word stress is the force by the system or object and pressure is the force on the system or object.
3. Similarity unit N/M2    .
   

example:- 

A man try to break the pencil and hence he applied some amount of forces on the pencil and according to the Newtons 3rd law every action having their equal and opposite reaction so here the reaction force applied by the pencil is stress and a force applied by  the man on pencil is pressure.