The interviewer is assuming that you have done a great deal of research before coming to the interview. This question is meant to test this theory, and to determine your understanding of the software development lifecycle. Your answer should confirm both of these points. It is an example of a hybrid operational and technical question. It asks you to define a concept relative to this profession and describe how you go about doing this job. When answering these types of questions, you should be direct and to the point. The interviewer is likely to ask several follow-up questions to explore this topic in more detail. Your answer should also be aligned with the requirements for this job, as defined in the job posting.