On Nikon lenses, “Micro” is Nikon’s name for a macro lens. The key difference is close-focusing ability: a Micro/macro lens can focus much closer than a typical lens of the same focal length, allowing very high magnification—often enough to fill the frame with very small subjects.

Macro lenses also usually have a longer focus throw, meaning the focus ring rotates farther from near to far focus. That makes fine manual focus adjustments easier, which is especially useful at close distances where depth of field is very thin. A tradeoff is that autofocus can be slower.

A non-macro lens of the same focal length is designed more for normal shooting distances and usually has a much longer minimum focus distance, so it cannot achieve the same close-up magnification. It may also have other specialized features unrelated to macro work.

So the practical answer is: same focal length does not mean same purpose. A Nikon Micro lens is designed for close-up, high-magnification photography and finer focus control.