Would someone define this term for me. I've heard and read it defined numerous times and the definitions were always circular or did not make any sense to me. For example, 'Micro-drag is something we can't see but the fish can'. Well, in the first place, if it's something that's visual how do we know it's there and how can we correct it if we can't see it? In the second place, if it's visible, then it's just 'drag'.

Allan