In PostgreSQL, the FOUND variable is a simple flag that helps you check if a query has found any results. It's like a "yes" or "no" indicator. 
 
1. When a query successfully finds one or more results, FOUND is set to true (or "yes").
2. When a query doesn't find any results, FOUND is set to false (or "no").

You can use FOUND in control structures like IF statements to make decisions based on whether your query found anything or not. It's a handy way to handle the outcome of a database search in your SQL scripts.