These are point scored from inside the key, an area on the court near the basket that is usually painted a different color than the rest of the court.
The key measures from the baseline below the basket all the way to the free throw line, which is 15 feet away. In the NBA the key is 16 feet wide, but that measurement changes with different levels of play.
Points scored inside the paint are usually high percentage shots like layups, dunks and post-ups and outscoring your opponent in the paint is usually an indicator of team success.