Machinist/məˈʃiːnɪst/ Definition 1 of 3Pro Tip 1/3Workplace Specific Used mainly for jobs in industries where heavy machinery is used. He was the best machinist on the factory floor. Pro Tip 2/3Not Just Operation Involves maintaining machines, not just operating them. The machinist is also responsible for regular machine maintenance. Pro Tip 3/3Skill Level Connotes a high level of skill and specialist training. After years of training, she became a licensed machinist.