Mushir is an Arab word meaning "counsellor" or "advisor". It is related to the word shura, meaning consultation or "taking counsel".
As an official title, it historically indicates a personal advisor to the ruler. In this use it is roughly comparable to the European titles of State Counsellor and counsellor of state.
In a military context, mushir became associated with the idea of the ruler's personal counsellor or advisor on military matters, and as such became the highest rank in Arab countries and the Ottoman Empire. It is used as the highest rank in most armed forces of the Middle East and North Africa, for armies, navies, and air forces. It is therefore equivalent to the ranks of Field Marshal and Admiral of the Fleet.