It is often used in words related to viewing, examining, or observing, such as:
* Telescope: An instrument for viewing distant objects.
* Microscope: An instrument for viewing tiny objects.
* Periscope: A device for seeing over obstacles.
* Endoscope: A medical instrument used to view the inside of a body cavity.
* Scope: The range or extent of something, often in terms of understanding or knowledge.
So, when you see "-scope" in a word, it usually tells you something about looking, observing, or examining.