Macro is a coil that has above average diameter and uses more wire so normally is higher in ohm ratings. Micro
coils are slightly smaller than average size
coils and they are typically lower in ohms which means that you can make longer
coils which in turn means more surface space which means more flavor, yay. Nano coils are even smaller than micro coils, these should be built with caution because they typically are very low in ohms, but once again can be built with more wraps to get higher ohms, which means better flavor. There are also super nano coils which are even smaller! can you believe it, but once again when you get into nano and super nano you must be careful that your ohms are not to low.
hope this clarifies stuff.