The difference between Bug, Error and Defect.

Error:

• The difference between expected result and actual result is error.
• Is an undesirable deviation from requirements  or Cosmetic.
• When we found any deviation from our required output in the development environment we call it as Error.

Bug:

• If that error comes at the tome of development stage before production then it is bug.
• Is an error found BEFORE the application goes into production or missing Functionality.
• when we found deviation from our System Requirement Specification (SRS) in the testing environment then we call it as BUG.

Defect:

• If that error comes after production then we say it is defect.
• Is an error found AFTER the application goes into production or missing Requirement.
• When some problem found in the production environment we call it as Defect.