Tensile Strength

There are three definitions of tensile strength:

Yield Strength: 

The stress at which material strain changes from elastic deformation to plastic deformation, causing it to deform permanently

Ultimate Strength: 

The maximum stress a material can withstand when subjected to tension, compression or shearing. It is the maximum stress on the stress-strain curve

Breaking Strength:

The stress coordinate on the stress-strain curve at the point of rupture