Meaning of 'Scatterer' and 'point scatterer' as opposed to just using the word 'target'?
I found this in your link:


  The radar equations (eq. 8 and eq. 10) are general equations for both point and area targets. That is, the scattering cross-section s is not defined in terms of any characteristic of a target type, but rather is the scattering cross-section of a particular target.