Bug: Deviation from the expected result. 
Defect: Problem in algorithm leads to failure.

A Mistake in code is called Error.

Due to Error in coding, test engineers are getting 
mismatches in application is called defect.

If defect accepted by development team to solve is called 
Bug.

A Mistake in code is called bug
difference between actual result and expected result

A mistake in coding called 'error'.If that error identified 
by test engineer called defect. That defect is fixed by 
developer is called bug.

Bug means lot of know and unknow mistakes in functionality
(code. while executing the test cases we will expect some 
result for that. if we have not get that result then we say 
it has bug. very simple is "Difference between actual 
result and expected result"

Bug:- A small deviation from the result is Bug
Ex:-If a calculator function is executed, then 10+20 should 
be 30 .If at all the result is displayed as 10, then it is 
abug
Defect:-Large deviation of the result from the expected is 
known as Defect 
(or)
unexpected behaviour of the actual value of specifications 
Ex:- If the specification says motor to rotate in 
clockwise,but if it all it is rotating in anticlock then it 
is a Defect

Bug: Logical deviation- It will not show any error but it 
will effect the system. (Ex: Online shopping- Suppose 
customer placed the order and got the order conformation 
but the details are not saved in DB or not reached the 
marcandize)

 
Defect : Nothing but error it will not effect the system.
It occures due to syntax or exceptions.

Defect : Mismatch, Deviation from expected results.

Simple defination: The mismatch between the expected and 
actuall is called bug or defect.
   When it with the developer or tester, it called as bug 
in technical aspect.
   When it goes to clients end, it is called as defect.

Error : Is an undesirable deviation from requirements 

Bug : Is an error found BEFORE the application goes into 
production 

Defect :Is an error found AFTER the application goes into 
production

A mistake in coding is called as Error
This is Error is found by Test engineer during Testing is 
called as Defect.
That defect is accepted by developer or fixed by developer 
is called as Bug.

Bug is nothing but a error in RUN TIME
Defect is nothing but error in application.

There is no difference between Bug and Defect

Meaning of bug and defect is  same but defect means
deviation from expected results...bug is also error and it
is kind of defect....

Error:Mistake found in code.
Defect: Mismatch found by the tester during testing.
Bug: Defect which is accepted by the developer to resolve.

There is no difference in bug and defect.These are just 2 
terminology used for same thing.It is flaws in component or 
system which can fail software to perform its intended 
function.Bug or defect is also called as fault.

A mistake in coding leads to 'ERROR' and when this error is identified by tester is called as a 'defect'.That means the difference between the  expected result and the actual result is called as a DEFECT.

When the defect is fixed by the developer it is called as a BUG.

Please correct me if I am wrong.


Thanks in advance.