How Did Biceps Get Nicknamed Guns?

"Welcome to the gun show!" You might have heard this phrase from an overeager greeter at an exhibition of projectile weaponry. Or, more likely, someone said this to you while flexing their muscly arms. The phrase "welcome to the gun show" plays off the popular nickname for biceps: "guns." It's a unique nickname as most other muscular groups tend to be nicknamed with shorter versions of their medical names, like "quads" in lieu of quadriceps or "traps" instead of trapezius muscles. So why do we call our biceps guns?

The upper arm is a collection of four muscles, inhabiting the front-facing (anterior) and back (posterior) sides of the arm, as TeachMeAnatomy explains. Biceps are the muscles located between your elbow and shoulder on the anterior side of the body, according to VeryWell Health. When you bend your elbow, the bicep is activated and it creates a bulged-out appearance. The other major muscles in the upper arm include the triceps and deltoid.

There are several theories behind the nickname guns, one of which attributes the moniker to the double meaning of the word "arm." In English, arms can refer to either humans' upper-body limbs, or to weaponry and ammunition, according to Merriam-Webster. This term encompasses all objects that are used as ammunition, including grenades, bombs, and even nuclear weapons, as well as guns. In fact, the term "small arms" means specifically handheld firearms like guns, according to Britannica.

Subsequently, some people theorize that the term guns came to be used to refer to our own arms. In some ways, it seems like a good nickname: Our actual biceps can be used as weapons in similar ways a gun may be; for example, boxers use their arms, and therefore biceps, as weapons o fight their opponent. However, there's no real evidence behind this theory outside of musings on message boards. Correlation does not equal causation, and though the intersection of the terms arms and guns in the military is interesting, it doesn't necessarily mean that the terms originated together.

Instead, some lexicographers have suggested an alternate theory behind the nickname, this one related to one of America's favorite sports: baseball.

The second main theory about the origin of the term guns, when referring to the bicep, is that it originated from baseball. At least one lexicographer, Jonathon Green, supports this theory, according to the podcast "A Way With Words." Green, whose studies focus on slang terms like guns, says the term may have originated during the 1920s. He claims it originally referred to baseball pitchers who were brought in as the "strong arm" to pitch a ball so fast that it would whizz past the batter.  AnswerToAll notes that in 1929 The New York Times referred to a pitchers' throwing arm as a gun; when brandishing a strong arm the player had a "good gun". The bicep, being one of the largest and strongest muscles in the arm  –  and also one of the most visible –  ostensibly served as the barrel of the gun.

This potential theory has been echoed by others online. However, like many theories about the origins of slang, it's difficult to definitively say where this nickname originated.