The rabbet joint as used in kitchen cabinets is similar to the dado joint, except the grove is cut on the edge of one of the pieces (see picture) rather than in the middle.
This joint is required when an edge connection is needed.
It is commonly how the backs of cabinets (and bookcases) are held in place.
The joint is typically glued, with very small nails or staples around the edge of the back as it’s necessary to ensure the small nails or staples hit the little wood lip created by the rabbet cut.
I hope this information is useful to you. Other details about cabinet construction is available in other articles.