Defect : From Producer Point of View , Any Requirement that 
is Missed out from that it was agreed to incorporate into 
product . This can be found during Verification , means 
Reviews  and not in validation like Testing ..
eg. I design a car as per the need of Middle Segment and i 
don't miss out what ever i have planned out ..

From Consumer Point of view , Anything that causes 
dissatisfacti0on ,irrespective of Requiremnts were fully 
incorporated or not ...
My customer finds that there in no Antilock system ..From 
my point , I have produced a DEFECT - fREE Product ,but it 
is still defective from customer point


Bug : When an unexpected thing happens from what is 
Expected , it is Bug .It happens in Testing  and in all 
validation techniques..
While testing the car , the car has to withstand 100 N,but 
it withstands only 80 N Force ..Its a bug !

Error : Syntax ,logical