While the basic rules of basketball are the same at the pro and college levels, the courts on which the games are played have some minor but important differences.
The most glaring difference is the distance of the 3-point line. The NCAA line is 20 feet, 9 inches all the way around. The NBA line varies between 22 feet in the corners to 23 feet, 9 inches at the top of the key.
The area inside of the free throw line is known as the lane or the paint. On a NBA court the lane is 16 feet wide, while it is 12 feet wide on college courts.
A NBA court has a restraining circle in the lane underneath the basket. This 4-foot circle was implemented to keep defensive players from standing under the basket to draw offensive fouls. The NCAA does not have this rule or the circle.
A NBA court has lines designating where substitutes wait to check into the game. It's directly in front of the timekeeper. NCAA courts do not have a marked area for substitutions.
The 3-point line is 20 feet, 6 inches in the professional WNBA and 19 feet, 9 inches for the NCAA women. The key is 16 feet wide in the WNBA and 12 feet wide in the NCAA.