A more thorough explanation:

Definition: A military board is a group of people who are appointed to either investigate and gather facts or provide advice to the military authority that appointed them.

Example 1: A military board is appointed to investigate an incident where a soldier was injured during a training exercise. The board will gather information from witnesses and review training procedures to determine what went wrong and how to prevent similar incidents in the future.

Example 2: A military board is appointed to advise the commanding officer on the best course of action for a particular mission. The board will review intelligence reports, assess the capabilities of available resources, and provide recommendations on how to proceed.

Both examples illustrate the definition of a military board as a group of people appointed to either investigate or advise. In the first example, the board is appointed to act as a fact-finding agency to determine the cause of the soldier's injury. In the second example, the board is appointed to act as an advisory body to the commanding officer.