Terminology vary from one phase to another in Software Application Life Cycle Software Application Life Cycle has 3 phases;
i) Development phase: In Development phase if developers find any mismatch they call it as Error or mistake
ii) Testing phase: In Testing phase if Testers find any mismatch they call it as Defect or Bug or Fault
iii) Production phase: In Production phase if Customers or End Users find any mismatch they call it as Failure