Surprisingly, I hear the question often. Engineers have to answer the question in interviews and in internal company communication. Make sure you have a short and concrete answer.
My answer sounds like this:
Quality Assurance is the term to describe the process that enables a software development company to deliver high-quality service.
As soon as we talk about the process, it makes sense to dive deeper into specific software development life cycle stages and discover, where we could find quality assurance imprints.