1. a person who trains or coaches someone, especially in sports or physical fitness
Usage: common in sports and fitness contexts
2. a substance or device that causes entrainment, the process of carrying along or incorporating something into a flow or mixture
Usage: technical; used in engineering, chemistry, and fluid dynamics

Examples

• She hired an entrainer to help her prepare for the marathon.
• The entrainer worked with the team three times a week.
• In the cooling system, the entrainer helps distribute the liquid evenly.
• The entrainer's expertise in biomechanics improved the athlete's performance.
• An entrainer device was used to mix the two chemical solutions.