The term 'moon jumper' is a job description for someone who works with cows. The crossword solutions for this term are COW, which is a three-letter word. A moon jumper is someone who herds and moves cattle from one place to another, usually at night when the moon is out. They use a variety of techniques to move the cattle, such as whistling, shouting, and using dogs. Moon jumpers must be knowledgeable about the behavior of cattle and have the skills to handle them safely.