Close up
Macro
As said above there is no universal rule (which is why Nikon can call their macro lenses "micro"). However in photographic worlds "true macro" is typically considered to be a magnification ratio of at least:
1:1
Size reflected on the sensor by the lens : size of the subject in real life.
Close-up is then basically anything that isn't as great as that magnification; whilst everything greater is just macro (although once you get to extremes words like super/hyper/extreme etc.. start appearing).
The world of science probably has its own formal definition.
THAT said macro to photographers also has a subject context meaning. That is to say a photo of a full bodied dragonfly or butterfly such as this
Might also be generally considered "macro" because its a butterfly. You see similar for things like the heads of roses/flower buds and other similarly "small" and truly "close up" shots counting. A little depends on how strict a definition the site/group is going for.