The word METL is a military acronym that stands for "Mission Essential Task List", which is a comprehensive list of tasks that are critical to the success of a military operation. There are several synonyms for the word METL, including mission critical tasks, vital tasks, essential functions, and critical operations. All of these terms convey the idea that there are certain tasks that must be completed in order for a mission to be successful. Whether you are a soldier, a manager, or a team leader, understanding the importance of mission essential tasks is essential for achieving success in any endeavor.