Scope in research would refer to the extent of your topic or its subject matter.
Scope can be approached from various angles in research. They include:
1. Context: an example would be to discuss scope in the context of Einstein's theory of relativity, Darwin's theory of the origin of species, Keynesian economics, Newtonian mechanics, Hawking's Steady State theory and Marxian historical and dialectical materialism.
2. Location: you can also situate scope in terms of geography. This is common with case-study research where you are conduct research on a particular topic with reference to a city, village, country, region or comparing them.
3. Time period: scope can equally be understood in time, for instance, when conducting a longitudinal study. Maybe a certain period in history.
Other ways of addressing the scope of your study may include the phenomenon you are examining, academic discipline and the topic in question.
Scope is important because it sets the boundaries of your research and helps you to proceed to answering research questions without much difficulty.