Bug- Conformed defected is called bug. It is said to be bug only at developer place.

Defect- Any Functionality is wrong then it is said to be defect by testers. It turns to bug in developers place

bug comes after completing the project

defect comes at developing time

BUG :It is a fault in a program which causes the program to perform in an unintended or unanticipated manner.

bug is a terminology which is used by Test engineers

Defect :Nonconformance to requirements or functional / program specification

defect is a terminology which is used by programmers

Defect: Missing requirements is called defect.

Bug:Dis satisfaction of the requirements.

Error:Which comes at the time of developement

Bug:Which comes at the time of testing(Pre-Release)

Defect:Which comes in Production or when client doing the system testing(Post-Release)

ragunathen Wrote:

Defect: Missing requirements is called defect.

Bug:Dis satisfaction of the requirements.

When tester verify the test cases All failed test cases are recorded as bugs directed for necessary action and recoded in defects reports. As a testing point of view all fail test cases are defects as well as found bugs. While development point of view if product doesn't meet the SRS or any feature that is to be required it is defects in that system. Who found this feature is not meeting his or her requirement he or she call it is bug in that product. Mukesh Chauhan Banaglore