I was looking at the color selections on ParacordPlanet website and wondered why they would preface some of the color names with "F.S" such as "F.S. Navy Blue". So, I emailed them and asked. They kindly replied that "F.S." stood for "Federal Standard". I don't think that it really means anything, and can be safely ignored. But if you have been loosing sleep at night over this, now you know. File this under trivia information.