Terminology
Interest in system quality has led to a proliferation of related terms. The term nonfunctional requirement has been used broadly in academic literature and some parts of industry, but it suffers from an unfortunate ambiguity: “nonfunctional” is an actual word that, according to Merriam-Webster's Collegiate Dictionary (11th edition), means something doesn't work. Some people have adopted the term “ilities” in recognition that many of these qualities end in the suffix “ility.” However, participants at a birds-of-a-feather session during the 14th International Conference on Requirements Engineering (RE 06) were unable to agree on a “one-size-fits-all” name for these kinds of requirements.