The term "feeling blue" originated in the Navy. Who knew?
22 Words and Phrases You Had No Clue Originated in the Military

Bikini: Named after the site of atomic bomb testing
In the summer of 1946, the United States tested its new atomic bomb on the Bikini atoll in the Marshall Islands. At the same time, French swimwear designer Louis Reard decided he needed an attention-grabbing name for his two-piece swimsuit invention. Reard likely chose the term “bikini” because he believed the style would be just as explosive as the bombs that were tested on the island of their namesake. Check out these 10 famous phrases you never knew were trademarked.

Deadline: A Civil War threat
Now a synonym for “due date” or “time limit,” the word “deadline” was originally used much more literally. During the Civil War, prisoners at one camp were confined to a pen and surrounded by a “deadline”; so called because if a prisoner crossed it, he would be shot dead.

Run amok: From Malayasian warriors
To “run amok” is to “go wild.” The phrase originated in the 18th and 19th centuries, when European explorers to Malaysia caught wind of a Javanese and Malay warrior class called the Amuco. This group of fighters believed those who lost a battle and survived would be punished with dishonor and death. Unsurprisingly, this belief led to maniacal and frenzied fighting tactics. For western onlookers, to act with disregard for consequences was to “run amok.”

Blockbuster: Named after a bomb
During World War II, this modern-day term for a box-office hit had a more sobering definition: A bomb big enough to take out an entire city block.

Bitter end: Coined by John Smith
This term first appeared in Captain John Smith’s 1627 publication, Seaman’s Grammar: “A Bitter is but the turne of a Cable about the Bits, and yeare it out by little and little. And the Bitters end is that part of the Cable doth stay within boord.” Basically, a bit is a post on the deck of a ship to which rope is wrapped around. When a rope is pulled out to the “bitter end,” it means there is no more rope left to be used.

Cup of Joe: The Navy’s drink of choice
When Josephus Daniels was appointed Secretary of the Navy in 1913, he abolished the idea of alcohol being served aboard ships. From that time on, coffee was the strongest drink available to sailors; over time, the drink became known as a “cup of Joe.” Learn some more stories of how iconic foods got their names.

Avant-garde: Troops that lead the pack
With a literal French translation to “forefront,” this term refers to the small party of troops sent out ahead of the main body of troops in order to plot a course and develop a plan of action.

SOS: Began with Morse code
While you might already know that SOS is a universal military distress signal, there are a few notable details surrounding it. First used by the Germans in 1905, this code isn’t actually an acronym. The letters were chosen for their striking Morse code transcription: dot-dot-dot-dash-dash-dash-dot-dot-dot. These are other common acronyms you’d never figure out.

Pea coat: Sailors’ coats
When sailors stood watch in the blistering cold, they often wore heavy coats made of pilot cloth, a course, twilled material. The fabric was sometimes referred to as p-cloth for short, and the coat that was made of it a p-coat; later, a pea coat.

Wallop: Comes from a huge defeat by a British admiral
After the French burnt down the town of Brighton, England, in the 1500s, King Henry VIII sent Admiral John Wallop to retaliate. Wallop is said to have sailed his fleet to Normandy and burnt down 21 towns and villages along the coast. Ever since, a “wallop” has meant a good beating.

Taken aback: A ship in the wind
When a ship gets caught in a sudden shift of wind, it is “taken aback.” The ordeal is particularly hazardous when the sails blow back against the masts, putting them in danger of breaking off. Here are some fascinating secret code words you’re not meant to know.

Bite the bullet: How soldiers coped with pain
To decide to begin an unpleasant yet unavoidable experience is to “bite the bullet.” But rest assured knowing your predicament is likely not as nasty as the soldiers’ with whom this phrase originated. Before anesthetics and painkillers were invented, wounded fighters would literally bite down on a bullet to cope with the pain of a surgical procedure. Why a bullet? The lead they’re made of is more malleable than stones and other battlefield finds, and therefore less likely to break the patient’s teeth.

With flying colors: A victorious Navy ship
If a Navy ship returned to its home port after battle with its flags—or “colors”—flying, it indicated that the ship had been victorious. Now, the phrase means to do something well. Here are some words we use all the time that were invented totally by accident.

Scuttlebutt: Sailors’ water-cooler talk
Meaning to gossip, the word “scuttlebutt” is a sailor’s version of water-cooler talk. Aboard ships, a scuttlebutt is a drinking fountain used by the crew. The chatter that goes on around it led to the word’s modern definition.

Murphy’s Law: From a pessimistic captain
“If there’s more than one way to do a job and one of those ways will result in disaster, then somebody will do it that way,” said Captain Edward A. Murphy to his assistant after testing a rocket sled at Edwards Air Force Base in 1948. The exchange led to the use of “Murphy’s Law”: If anything can go wrong, it will.

Hot shot: Heated cannonballs
In modern usage, a “hot shot” is someone of great importance. One possible origin of the term could be the use of heated cannonballs—a hot shot—and the men who loaded them. The task would have required great skill and been an important role in battle. Another origin could be someone who shoots recklessly.

Chewing the fat: Vintage food for men at sea
Before ships were equipped with refrigerators, salted beef—which was cheap and would keep well—was standard fare for men at sea. One piece of the jerky could often be chewed for hours. Now, the phrase means to have an informal chat with someone—something the sailors likely did whilst “chewing the fat.” Check out these funny military cartoons that’ll make you appreciate our vets.

Feeling blue: When a ship lost an officer
If a ship lost its captain or one of its officers during its voyage, it would fly blue flags and have a blue band painted along its hull while returning home. Now, the term means to feel sad.

Over the top: Bold in battle
To be “over the top” is to act in an excessive or unnecessary manner. The term was originally much more literal. In battle, being over the top meant to launch an attack by climbing over the sandbag parapet in front of a trench. It soon became synonymous with any dangerous venture.

Loose cannon: Potential danger on a ship during a storm
President Theodore Roosevelt was the first to use this term when he told a journalist he didn’t “want to be the old cannon loose on the deck in the storm.” His reference was spot on: Before ships were equipped with fixed-turret guns, cannons were mounted on wheels and rolled between gun ports. A “loose cannon” could break free in choppy waters, potentially harming sailors.

Devil to pay: Annoying chores at sea
On a wooden ship, the “devil” was the longest seam on the ship’s hull, and caulking was done with a type of tar called “pay,” or pitch. No one wanted the dangerous and miserable job of caulking this seam. To have the “devil to pay” was an unpleasant task.

Know the ropes: Basic sailors’ knowledge
This phrase was originally written on sailors’ discharge papers to show they had only a basic understanding of the names and uses of the main ropes onboard. Now, the term is used to denote expertise. Next, get a look at these hilarious code words you won’t believe the military actually used.