In many European languages, the term Major refers to a military rank, denoting seniority at one of usually various levels of rank, for example: "Sergeant-Major" denoting the most senior ranking sergeant of a large military unit; "Captain-Major", denoting a mid-level command status officer (immediately superior to the rank of a land-forces Captain but immediately subordinate to the ranks of Colonel and/or Lieutenant Colonel; and "General-Major" or "Major-General", denoting a senior-ranking general officer. A major is typically in charge of a company, squadron or artillery battery in the army.

Most often, when the term 'major' occurs unhyphenated, in conjunction with no other indicator of rank, the term refers to the rank just senior to that of a land-forces 'captain'. In some countries, most notably in France, an unhyphenated "major" derives from "sergeant-major", a senior-level sub-officer rank. Much more rarely, the unhyphenated term has also often been used to denote senior-ranking general officers, usually in countries where European languages are foreign and interpreters fail to recognize the multiple levels of 'major' ranks in European militaries, and is used to indicate the most senior of all generals, or in countries of recurring civil war and upheaval, where it is not all that uncommon for a low-ranking officer to rise in rank quite rapidly and become the leader of some faction or another, and in order to avoid the potentially deadly mistake of mis-addressing a colonel as "captain" or a general as either "captain" or "colonel", it is simply safer to address anyone of unknown rank as "major" until otherwise corrected, for its convenient ambiguity.

Non-commissioned rank

In the French military, a major is the most senior non-commissioned rank. This rank can only be awarded to a senior NCO (adjudant-chef), after a very selective exam. Officially it is not a non-commissioned rank, but an intermediate rank between non-commissioned and commissioned.

Use as a suffix

The rank of Major may still be found in its original form as a suffix (either hyphenated or not), to denote an officer more senior to the base rank. As a suffix, major derives from a comparative adjective major 'greater' and 'senior' following the modified Romance language noun; e.g. Adjutant-Major, and Colonel-Major. It is also still commonly used in the rank of Sergeant Major, and is also used in ceremonial appointments such as Drum-Major and Pipe-Major.

In Argentina, the armed forces all use the rank of sub-officer-major as the highest non-commissioned rank. The army and air force also use the officer rank of major. The army has a rank of colonel-major, but this is essentially an automatic promotion for long-serving colonels rather than a functional rank in its own right. The Argentine National Gendarmerie uses the rank of commandant-major, which is roughly equivalent to a colonel or chief superintendent in the commonwealth.