The Onesie – Its Definition and History


Nowadays, the “onesie” has become a popular term referring to a loose-fitting casual jumpsuit for adults. The history of the onesie dates back further than you may think. If you are a fan of onesies, you might find its history pretty interesting.

The onesie is usually made of knit cotton (the material of most sweatshirts), fleece or chenille (a type of fabric which is supposed to resemble the fur of a caterpillar).

The early history of the onesie

While onesie is a common term nowadays (mostly in the United States) for adult clothing, onesie was originally a bodysuit for infants.

The ancestor of the onesie, pajamas, were first introduced in Britain during the 17th century. The trend was only fleeting; however, they returned in the late 19th century.

By the 1880s, several retailers had begun selling tops and bottoms as one, which were the earliest versions of the onesie. Eventually, the loungewear (or nightwear or sleepwear) increased in popularity. By the 1930s, the demand for loungewear soared. Even men had started to wear one-piece pajamas as elegant evening wear.

The boiler suit: the hardest-working onesie

Another early iteration of the onesie is the boiler suit. It is a loose-fitting one-piece protective garment worn for heavy manual work. It is usually worn by plumbers, brick-layers, mechanical workers, painters, fighter pilots, engineers, etc.

The term “boiler suit” was first mentioned by the British tabloid Sunday Express in October 1928. The American counterpart for “boiler suit” is “coverall” (or “coveralls”).

Churchill as the inventor of the siren suit

The popularity of the one-piece pajamas reached their peak when it was revealed that no less than the British prime minister Winston Churchill started wearing them. He raved at how comfortable they were. At the time, one-piece pajamas were popularly referred to as “siren suits,” which were similar to boiler suits.

Most history sources cite that it was Churchill himself who designed and invented the siren suit, for practical reasons. It was the onset of the Second World War, and air raids were becoming an omnipresent threat in the UK. The siren suit was easy to slip on, making it quick to wear over one’s clothes in the event of an air raid. Churchill wore a pinstripe suit during the war years and then for several artistic portraits during the 1950s.

Despite Churchill’s endorsement of the onesie, it didn’t take off immediately with the adults. More often than not, people would use the onesie for their babies to keep them warm and protected. The onesies for babies even saw a massive demand during the post-war “baby boom” years.

The return of the onesie as an adult clothing

 The onesie finally made a comeback as an adult clothing during the early 1970s. A book by Geoffrey Hoyle entitled, 2010: Living in the Future, made a bold prediction: that everyone would be wearing jumpsuit-style clothes in the future. And Hoyle couldn’t be more right.

The jumpsuit – from the sky to the catwalk

Another iteration of the onesie is the jumpsuit, which is the tight-fitting version of the boiler suit or coverall. It was originally designed as a functional garment for the parachuters or skydivers. Jumpsuits protected them from the colder temperatures associated with higher altitudes. It also allowed them to have easier access to the important handles and grips that they could use during their flight and descent.

Aviators and astronauts also have their own modified versions of jumpsuits. They have special features such as insulation to keep the body warm against colder temperatures. Motor racers and race car drivers wear fire-retardant jumpsuits to protect them from the flames in the event of a crash.

As the jumpsuit evolved, it found its way into the world of fashion, becoming what we call today as the onesie.

The onesie today

Today, onesies are worn by pretty much everyone – both by men and women of all ages. It’s probably because onesies are so snug to wear and are easy to take on and off. It comes in many sizes, colors and designs. Some of them have animal designs or designs of several cartoon or comic book characters.

The clothing manufacturer Jumpin Jammerz was largely responsible for the adult onesie craze. When the company first launched one-piece loungewear for both men and women in 1998, they immediately took off. Jumpin Jammerz initially made the loungewear as a gimmick for company founder Steve Pandi and his rock band. However, their onesies became an incredibly successful and fast-selling fashion item in both the US and the UK.

Jumpin Jammerz’s onesies have also found their way into television. They have been spotted in several  TV shows such as MadTV and CSI: Las Vegas.

Even many Hollywood A-listers have caught on the onesie trend. Celebrities such as Miley Cyrus, Lucy Hale, Liam Hemsworth, Katy Perry, Taylor Swift, Cara Delevingne, Bella Thorne, Ariana Grande, Rihanna, Kourtney Kardashian, Justin Bieber, and even Brad Pitt and Dwayne “The Rock” Johnson are photographed rocking the onesie.

Onesie Buying Guide

Onesies are basically jumpsuits that can be worn by adults as pajamas or for more functional purposes. Modern-day onesies commonly used by people are designed to provide comfort and coziness for a day of lounging. However, for them to be comfortable, it is essential that you choose the perfect one for you. By looking at the design for the onesie, the fabric it uses, and its washability and size, you can find one that suits you best. 

Choose a Onesie Design

There are many kinds of onesie designs, and depending on your preferences, you may like some more than others. Onesies come in footed, footless, hood, no hood, zipper, and snap styles. 

Footed onesies come with attached socks which are perfect if your feet tend to get cold easily. However, if you plan to wear these in the house, note that you will likely not be able to wear any kind of slippers. Additionally, footed onesies tend to get dirty and wet easily, making them uncomfortable to wear for extended periods.

Hooded and no-hood designs are also pretty popular. If you want a fun onesie, a hood can help add cat or bunny ears to make the hoodie themed. Zipper and snaps refer to how the onesie opens up. Zippers make getting into and out of the onesie easier, but you won’t be able to wear it if it breaks. 

The Fabric

Like clothes, onesies come in a variety of fabrics. Depending on your preferences and the weather, you should choose a material you feel comfortable in. Fleece onesies are perfect for winter because they are soft and can keep you cozy. Cotton onesies aren’t as warm but are more breathable, making them ideal for summer or all-year-round wear. Polyester blend onesies are also an option, as they are durable and breathable. 


When purchasing a onesie, it is essential that it is washable and that the color does not fade or the size does not change when you put it in the wash. This is incredibly important for footed onesies, as they get dirty quickly. When washing onesies, ensure you turn them inside out and hang dry them instead of putting them in the washer. 


Onesies come in all shapes and sizes. You can get form-fitting ones or choose a baggy one to use as a pajama. Ensure that your onesie is not too large, or you may find it challenging to handle all the material and may trip on it if it’s too large.


Compared to other fashion trends, the onesie has stood the test of time. Its comfort, ease of use, fun factor, and universal appeal have made the onesie so popular. There is no doubt that the onesie will stay in the years to come.

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