Headless simply means without head, but in technical term headless often referred to as a system that works without any graphical user interface (in short GUI).
For example, servers in the data centers are headless, hosted owners usually use SSH shell (command line) to communicate with it. Similarly, web application services use API calls to add, modify, or delete values from the database.
In the modern computer application programming world you’ll read and listen to words like headless, faceless, ghost, headless browsers, headless environments, and headless servers; all those terms are one and the same with a different way of using it.
Related: What is a headless server?
To access and manage such a system we need to console-based tools.
Ever wondered why in this modern age such a headless thing exists?
It is simple because headless systems are lightweight, puts no stress on hardware, and easy to manage and there is little or no chance of error from the software end.
So, now you are aware of this headless terminology and never get confused with jargon.