What defines a bug or defect in software testing?

A bug or defect in software testing is best defined as the result of an error or mistake. This encompasses a broad range of issues that can arise during the software development process, including coding errors, design flaws, or any deviations from the expected behavior of the application. Essentially, when a programmer or team member makes a mistake—whether it's incorrect logic, misunderstanding requirements, or overlooking a critical component—it can lead to a defect in the final product.

Understanding that defects stem from mistakes clarifies that they are not solely limited to incorrect outcomes experienced by users, but originate from the development process itself. This viewpoint reinforces the importance of rigorous testing as a means of identifying and addressing issues before the software is released to users, ensuring that the final product meets the specified requirements and functions as intended. By acknowledging that defects arise from errors, testers can better focus their efforts on prevention and resolution during the development lifecycle.