Here I am trying to explain what is the difference between Error, Defect and Bug in Testing.
You can see my previous posts on What is Automation Testing?, Bug Life Cycle and Tutorial on regression testing .
If a developer finds a mistake in coding then that mistake is called as Error/Flaw.
If a tester detected any mistake in software coding then that mistake is called as Defect/Issue.
If a testers defect was accepted by developers to fix then the defect is called as Bug. Sometime customer facing problems in software after release that is also called as Bug.