Defect, Bug, Error, Failure in Software Testing

Bug:-

If a tester tests the application to find a mismatch or any mistake in an application during software testing then it is called a bug.

Bug can be found by testers, clients, or end-users.
The bug will be locked by QA and proceed to the QA lead, they will analyze and send it to the development team. if the development team approved this then it is called a defect.
Defect:-
The confirmed bug of the system is called a defect that was found by the QA team and approved by the development team. If a bug is not confirmed then it is only a bug, not a defect.

If the variation between the actual result and expected result will be shown by the client or developer then it is also a defect.

Error:-
The error means if any problem occurs by program code during compilation and execution then it is called Error.

The error will be handled by a technical team that was managed by the development team during coding.

Failure:-
If an application will be crashed completely or partially then it is the failure of an application. if data will not be posted to the server then it is called application failure.

Url is not opened then also it is a failure. the web application provides 404 error if page not found that is also the part of failure. Failure always will be raised after deployment of an application by the Client, Developer, or others.

Defect Life Cycle or Bug Life Cycle