This term is commonly seen when describing camo, but what is it exactly?

Macro patterns are large patterns that are intended to break up silhouettes at a distance. They are often seen as large contrasting segments across a uniform or vehicle. The downside is that it tends to lose it's effect at closer ranges.

The M81 Woodland pattern was designed to work best several hundred meters away, and is a great example of a macro camouflage scheme.