In sciences such as physics, geography, astronomy, meteorology and statistics, the term scale or spatial scale is used for describing or classifying with large approximation the extent or size of a length, distance or area studied or described. For instance, in physics an object or phenomenon can be called microscopic if too small to be visible. In climatology, a micro-climate is a climate which might occur in a mountain, valley or near a lake shore, whereas in statistics a megatrend is a political, social, economical, environmental or technological trend which involves the whole planet or is supposed to last a very large amount of time.
In physics, the concept of scale is closely related to the more accurate concept of order of magnitude.
These divisions are somewhat arbitrary; where, on this table, mega- is assigned global scope, it may only apply continentally or even regionally in other contexts. The interpretations of meso- and macro- must then be adjusted accordingly.