Common slang words, phrases, and idioms that surprisingly originated from the Navy

Photo Credits: Smith Collection / Gado / Getty Images.
Photo Credits: Smith Collection / Gado / Getty Images.

For centuries, life aboard ships forged a distinctive language among sailors—born from battling storms, tending to shipboard duties, visiting far-off ports, and sharing the tight-knit bonds of life at sea. Over time, many of these nautical terms drifted ashore, quietly becoming part of everyday English without most people realizing their maritime beginnings.

Curious about the seafaring origins of words and phrases you use every day? Embark on this linguistic voyage—you might be surprised at how much of modern speech was shaped on wind-swept decks and among the creaking rigging of centuries past.

Knot

Chip log with a timer placed beside it
Photo Credit: Rémi Kaupp / Wikimedia Commons CC BY-SA 3.0

A knot is the classic unit used to measure a ship’s speed, and its origins reflect the resourcefulness of early sailors. Long before technologies like GPS, mariners relied on the log line—a straightforward yet clever tool. A weighted wooden board was cast over the stern, attached to a rope marked at regular intervals with “knots,” each spaced 47.33 feet apart.

As the ship moved forward, the rope unwound behind it. Sailors timed a 28-second interval using a sandglass and counted how many knots ran through their hands. That number represented the vessel’s speed in nautical miles per hour—a practical technique whose influence continues to guide navigation across the world today.

Let the cat out of the bag

Cat o' nine tails against an orange backdrop
Photo Credit: USS Constitution Museum / Wikimedia Commons / Public Domain

The phrase “letting the cat out of the bag” originated in naval slang and referred to the act of flogging. Here, the “cat” represents the cat o’ nine tails—a powerful whip with multiple tails kept inside a cloth bag. Sailors knew punishment was imminent when an officer removed the whip from its bag.

Ship’s husband

Workers attending the launch of La Seine at the Shipyards of France
Photo Credit: AFP / Getty Images

When a ship is heading back to port for repairs, sailors often casually refer to it as returning to its “husband.” Here, “husband” denotes the person overseeing the shipyard responsible for restoring the vessel to seaworthy condition.

Carry on

Drawing of a frigate at sea
Photo Credit: Bettmann / Getty Images

Most are familiar with the British phrase, “Keep calm and carry on,” but were you aware that the last part has naval origins? On days that experienced particularly good weather – gentle winds, if we’re being specific – the order to “carry on” would be given.

This indicated that all available sails should be raised.

In through the hawsepipe

Hawespipe attached to a red dashboard
Photo Credit: S.J. de Waard / Wikimedia Commons CC BY 2.5

“In through the hawsepipe” is Navy slang used by seamen who become officers through non-traditional means, describing their rise through the ship’s ranks. In this context, it signifies starting from the very bottom. The hawsepipe, also known as the hawsehole, is the hole in the bow through which the anchor cable passes.

Scuttlebutt

San Giorgio scuttled in the water
Photo Credit: SeM Studio / Fototeca / Universal Images Group / Getty Images

“Scuttlebutt” in naval slang refers to a rumor. Its origins trace back to “scuttle,” meaning the deliberate sinking of a ship by creating openings in its hull, and “butt,” the common water receptacle where sailors would gather for conversation. Essentially, it represents the impact rumors can have on morale.

Taken aback

Penang sailing in the English Channel
Photo Credit: George Greenwell / Mirrorpix / Getty Images

While it might not seem like a phrase of naval origin, the fact is that “taken aback” is a form of Navy slang! Modern speakers use it to describe when they’re shocked or surprised about something, but it originally referred to when a sudden strong gust of wind hit a ship’s sails and pushed them in the opposite direction.

He knows the ropes

Ropes extending from the front of a ship
Photo Credit: Maciej Karon / Unsplash

This term, commonly used in the English language, was originally used to describe a novice sailor. It would be printed on their discharge and meant they knew the names and purpose of a ship’s main ropes… Basically, it informed their superiors that they knew the very basics of seamanship.

Spinning a yarn

William Kent speaking with three women on a boat
Photo Credit: Fox Photos / Getty Images

Today, to spin a yarn means to tell a story, one that’s perhaps slightly exaggerated. Its seagoing origins date back to naval officers who believed that, if seamen spent too much time telling stories, then no work would be done.

At least once a week, a ship’s crew would have to unravel old lines of rope. During this, the men could converse and tell stories as much as they pleased, and the time became known as “spinning yarns.” Eventually, telling a tall tale turned into spinning a yarn.

Devil to pay

Gotheborg at sea
Photo Credit: VALERY HACHE / AFP / Getty Images

This expression is used today to describe that something unwanted is looming. However, some claim the term originates from the despised task of waterproofing a wooden ship’s longest seam along the keel. This is sometimes disputed, but there are many who believe it.

The seam was named the “devil” and would be “paid” or covered by tar. Paying the devil was an extremely unpleasant and difficult job, and the name was eventually used to describe any unwanted situation.

On the fiddle

Fiddler performing for a crowd
Photo Credit: Newtown Graffiti / clusternote / Wikimedia Commons CC BY 2.0

The fiddle was a raised lip around the edge of a sailor’s plate. If food touched it, this meant he had too much and was described as being “on the fiddle.” This could earn him a whipping.

Bokoo

Painting of ships at sea
Photo Credit: Print Collector / Getty Images

A sailor may say the word bokoo, meaning “many.” This actually comes from the French word, beaucoup, which has the same meaning. The spelling was simplified over time and is an example of the many words from other languages that have been incorporated into Navy slang when traveling the world.

Square meal

Sailors eating and drinking on the deck of a ship
Photo Credit: Touring Club Italiano / Marka / Universal Images Group / Getty Images

“Square meal” is a Navy term that’s surprisingly literal in its origin. Sailors once ate from sturdy, square-shaped wooden plates, designed to stay put during rough seas. These plates often had raised edges—called “fiddles”—to help keep food from sliding off when the ship rocked.

If a sailor managed to spill food beyond the fiddle line, it was jokingly said they were “on the fiddle”—a phrase that later came to imply cheating or bending the rules. While “square meal” today simply means a hearty, satisfying dish, its roots lie firmly on the rolling decks of naval vessels.

Peacoat

Black peacoat against a white backdrop
Photo Credit: Sirimiri / Wikimedia Commons / Public Domain

A peacoat is a thick jacket worn by sailors during bad weather. A potential origin for the name comes from the material from which it’s made: pilot cloth. Sailors would refer to the coarse, heavy fabric with the initial “P,” instead of pilot, which eventually became the “pea” in peacoat.

Jesse Beckett

Jesse is a U.K.-based writer for Tank Roar, passionate about military history and storytelling through digital content. With a special focus on tanks and ships, Jesse brings a deep enthusiasm for historical narratives to every piece.