That's one misleading title man, haha!
Simply put, as you turn you tone knob back, you're bleeding the treble away. So at one end, it's very trebly, at the other extreme, it's not.
There are two tone knobs on your strat.
Bottom knob controls the bridge and top controls the neck.
If your selector is on neck, it's purely for that, if it's on neck/middle, then it changes the amount of balance between the neck and the bridge, and so on.
Play around with it, it's a great tone shaping tool that is always overlooked.