Nomenclature is a system of naming military equipment. Sounds simple, but of course, they’ve got to do it the “Army way.” We’ve all seen the Army’s long descriptions to name something simple. Take for example, “TRAILER, TANK, WATER: 400 GALLON, 1-112 TON, &WHEEL M I112 (NSN 2330-01-389-9073) WITH STAINLESS STEELTANK BODY, 1, EA” which is a water trailer or “water buffalo” as it’s known in Army slang. This longwinded naming convention sounds over the top, but with tens of millions of items in the inventory, it’s a much-needed system. Unfortunately, it remains confusing, and there are several naming conventions in place. 

Although the current Army standard was updated just a few years ago, it was originally known as the Ordnance Nomenclature System and dates back into the 1800s. It’s important to note that in its early use as an Ordnance mark designation, weapons were numbered based on the year of adoption; for example, M1893 Mauser. Nowadays, systems are generally numbered in serial order by type. 

Specifically, the Army Nomenclature System is designed to help avoid confusion by accurately referencing items which may have similar names to other items of their category. It applies to weapons, ammunition, vehicles, explosives, components of those items and other equipment associated with handling/storage/management of these items. 

Other pieces of equipment such as radios and electronics use completely a different model designation system, which I’ll briefly mention later. This article only discusses equipment used by ground forces. Aviation nomenclature is an entirely different animal.

The nomenclature itself consists of what is called the Approved Item Name (AIN), an extended modifier (if applicable), and the type designation, which was originally referred to as an ordnance number. The AIN is presented in all capital letters, is not abbreviated, and is followed by a colon. You see a fitting example in the opening paragraph. 

Next is the type designation, which begins with an M and is followed by a model number; there is no hyphen or space. For example, “M4A1.” However, you may run across XM prefixes, with the X signifying developmental. Generally, once a system completes all developmental and operational testing required, it is type classified for general issue and loses the X. Suffixes such as A1 are used to designate upgrades to the equipment. 

In order to identify a piece of equipment properly and completely, you have to use both the Approved Item Name and Extended Modifier. I’ll give an example. Over time, M45 has designated an anti-aircraft mount, a light fixture, a protective mask, a tank and a pistol, as well as other products I’ve probably missed. But when you specify, “MASK, CHEMICAL-BIOLOGICAL: AIRCREW M45” it becomes much clearer.

Over the last few years, the Army has made efforts to not reuse certain designators, at least by equipment type. The recently adopted Next Generation Squad Weapon rifle was originally designated XM5, but Colt had created an M5 carbine in the 1990s. There was also an M6 carbine on the commercial market, so to avoid confusion, the Army skipped ahead to XM7. Once it has passed testing this fall, it is anticipated it will be adopted for replacement of the M4 carbine for close combat forces consisting of infantry, cavalry scouts and combat engineers. At that point, it will become simply the M7. 

Although this naming system is peculiar to the Army, the other services often use equipment which was designated by the Army due to their development and management responsibilities. Take for example the M4A1 Carbine. Although it has been in use by all five services, it retains the M4A1 designation assigned by the Army when it was initially type classified in the early 1990s. 

Alternatively, the Navy and sometimes the Marine Corps use a Mk ordnance designation system (pronounced mark) with versions designated by a Mod suffix designating a modification. This system is used by several allied navies as well. 

Weapons aficionados will note oddities such as the Mk19 Mod0 40mm automatic grenade launcher, which is used by four of the U.S. Armed Services and Coast Guard. Despite ground combat service, it was actually developed by the Navy during the Vietnam war for use on patrol boats and so retains the Naval Ordnance designation. Likewise are several specialized versions of the M4 carbine that are used by various elements of U.S. Special Operations Command and were developed by Naval Surface Warfare Center — Crane. Another anomaly is the U.S. Air Force’s use of an aviation ordnance designation for their use of specialized versions of the M4 carbine. In particular, the GAU-5/P is a take-down version of the carbine designed to fit in ejection seats. “GAU” means Gun Aircraft Unit.

Fortunately, radios and other electronics designations have been standardized among the services since the end of World War II. The Joint Electronics Type Designation System (JETDS) was previously known as the Joint Army-Navy Nomenclature System (AN System. JAN) and the Joint Communications-Electronics Nomenclature System.

JETDS uses a combination of Type Designation and an Item Name. You’ll note that military radio designations begin with AN for Army Navy, followed by a slash. The three letters after the slash designate the role of the item. Many who served in the military have used one of the Single Channel Ground Radio System (SINCGARS) family’s AN/PRC-119. PRC is used to designate Portable, Radio, and Communications. Mounted in a vehicle, the P would become a V; installed on an aircraft, an A would be used. There are various combinations of designator letters that can be referenced easily online. Accessories like antennas and security devices use other designators to denote model. Fortunately, these can easily be looked up online as well.

Aside from the tri-service aviation nomenclature system, there are a few others in use within the Department of Defense, but they are rare. Despite increasing standardization, the various systems remain confusing, but fortunately, we are well past the days of the same piece of equipment being named differently by various designation systems.