Quality Assurance refers to administrative and procedural activities implemented in a quality system so that requirements and goals for a product, service or activity will be fulfilled. It is the systematic measurement, comparison with a standard, monitoring of processes and an associated feedback loop that confers error prevention. This can be contrasted with quality control, which is focused on process output.
You can read the following thread to understand the difference between QA and testing (quality control): What is the difference between "testing" and "quality assurance"?
What I'd like to understand is whether there is a place for QA engineer who is not a tester in Agile/Scrum. Agile is deliberately short on processes and documentation (its even in the manifesto), and that's what QA specialize in. So should there even be a QA engineer in Agile?
I myself am not a QA engineer (I am a test lead), but I have a friend who is, so that's why I am asking.