"What is x?" as a non-question title

I am working on my PhD thesis. I would like to have section title like "What is x"? (Specifically, "What is Information Flow Security?") However, I wish to avoid rhetorical questions in my academic writing, and so I was wondering if there is a way in which I can word this title such that it is not a question. Something like "Defining Information Flow Security" but not that, because definitions are something else entirely and I won’t be offering a formal definition at this point in the work.