Here is the difference in plain terms:
- Lithic scatters
These are the sites you see on the ground: clusters or spreads of stone fragments left behind from stone toolmaking. A lithic scatter could include flakes, cores, broken tools, or other debris. It is the visible archaeological footprint of tool production or use. - Debitage
This is the waste material created when someone was shaping stone into tools. Think of the wood shavings on the floor after whittling. Debitage includes flakes, chips, and fragments that were not intended to be used as finished tools. Archaeologists study debitage to determine what kind of tools were being made, the techniques used, and sometimes even who was doing the knapping. - Flakes
These are specific pieces of stone struck off from a larger stone (a core) during toolmaking. Some flakes are just waste (part of debitage), but others can be shaped further into tools themselves (like scrapers or blades). So, flakes can be both by-products and usable tools, depending on how they were treated afterward.
To put it together:
A lithic scatter is the overall archaeological site, which contains debitage (waste pieces) and sometimes flakes (which may be either waste or turned into tools).