Holes on golf courses are the designated areas where a golfer must hit the ball in order to complete the hole. There are typically EIGHTEEN holes on a golf course, which is why the crossword solution for the term 'holes on golf course' is 'EIGHTEEN'. Golf courses are designed with a variety of obstacles and hazards, such as sand traps, water hazards, and rough terrain, which make it more challenging for the golfer to reach the hole. The goal of the game is to complete each hole in the fewest number of strokes possible.