Definition of perception How do I describe this?


  It is the formulation of a conception of an idea about a particular object of experience.


What I am wondering is what the difference is between the above and:


  It is the formulation of an idea about a particular object of experience.
Buddhism teaches there are five aggregates. Consciousness (vinnana) is one aggregate; feeling (vedana) is another aggregate; perception (sanna) is another aggregate; and mental formations (sankhara) are another aggregrate. A 'conception' is a 'sankhara' ('mental formation') and is not a perception. 

'Perception' is distinguishing differences in conscious sense impressions (such as different shades of color) and is inseparable from consciousness; as follows: 


  Perception, perception': Thus is it said. To what extent, friend, is it said to be 'perception'?" 'It perceives, it perceives': Thus,
  friend, it is said to be 'perception.' And what does it perceive? It
  perceives blue. It perceives yellow. It perceives red. It perceives
  white. 'It perceives, it perceives': Thus it is said to be
  'perception.'
  
  Feeling, perception &amp; consciousness are conjoined, friend, not disjoined. It is not possible, having separated them one from another,
  to delineate the difference among them. For what one feels, that one perceives. What one perceives, that one cognizes. 
  
  MN 43


Where as a 'conception' is a subjective idea or thinking that is added onto a conscious perception, as follows: 


  Dependent on eye &amp; forms, eye-consciousness arises. The meeting of the three is contact. With contact as a requisite condition, there is
  feeling. What one feels, one perceives. What one perceives, one
  thinks about.
  
  MN 18
  
  
  
  He perceives fire as fire. Having perceived fire as fire, he conceives himself as fire, he conceives himself in fire, he conceives
  himself apart from fire, he conceives fire to be ‘mine,’ he delights
  in fire. Why is that? Because he has not fully understood it, I say.
  
  MN 1


The difference between 'perception' and 'conception' is (when conscious sense experience occurs) perception is unavoidable; where as 'conception' is avoidable. 

Right now, my mind cannot avoid perceiving the 'shapes' &amp; 'colours' that make up my computer. However, my mind can choose to not make 'conceptions' about those 'shapes' &amp; 'colours'. In other words, those shapes &amp; colours can be observed without the conception of the thought or word "computer".