Adaptor vs. adapter?

Adapter” and “adaptor” are two spellings of the same word, although “adapter” is the more common spelling.

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What is the difference between adaptor and adapter?

If you’re looking for a hot debate regarding spelling variants, look no further than the noun “adapter,” which we can also spell as “adaptor.” 

Is there a correct spelling for British vs. American English?

Between the two spellings, “adapter” is more widely used. But since “adaptor” was once more common for British English, many writers still use this spelling outside of the United States. 

Google Books Ngram Viewer shows that the prevalence of “adaptor” within British English arrived just before 1940 but lost popularity to the “adapter” spelling variant by 1991. Since then, “adapter” has slowly become more frequent outside the US, but neither spelling is necessarily wrong.

Professional adaptors vs. adapter mechanisms?

Another common argument you’ll encounter with these variants involves the spelling of professional adapters/adaptors (i.e., people who adapt written composition for a living) and adapter/adaptor mechanisms.

Some writers insist that “adapter” is correct for “script adaptors” (people) and that “adaptor” is best for objects that adapt or connect incompatible parts or systems. However, every standard English dictionary lists both variants as acceptable spellings, and that’s whether you inquire Merriam-Webster’s Dictionary, The American Heritage Dictionary of the English Language, Cambridge Dictionary, or the Oxford English Dictionary

Style guides on adapter vs. adaptor

If you’re writing for a publication that follows a unique style guide, you might need to use one particular spelling over another (regardless of what a dictionary states). For example, The Guardian-Observer Style Guide instructs their journalists to use “adapter” for “someone who adapts” and “adaptor” for an “adaptor plug.” (Note: This rule is not always followed in practice.) 

In contrast, The Associated Press Stylebook does not specify a preference for “adapter” or “adaptor.” According to the AP Stylebook’s online dictionary, either spelling is appropriate for “a person or thing that adapts,” “a contrivance for adapting apparatus to new uses,” or “a connecting device for parts that would not otherwise fit together.

What does adapter mean?

The noun adapter (also spelledadaptor”) references anything that adapts, meaning it can be a person or thing that:

  1. Modifies or creates a new purpose or use of something;
  2. Adjusts to new conditions, or; 
  3. Translates or alters a novel or musical composition for filming, broadcasting, or theater performances (such as a writer or musician). 

Sentence examples:

  • “The nylon cord adapter transforms any ill-fitting shirt to a dress or crop top.”
  • “The ideal server is an able adapter who can manage both low and high-energy shifts and unpleasant guests.”
  • “The British newspaper reports the young actor and screenplay adapter enjoys a niche fan base in Finland, Denmark, and New Zealand.”
  • “The adapter of the ancient play made several references to famous sculptors and painters of the time.”

When referencing special devices, an adapter is something that connects incompatible pieces of equipment, optimizes a device’s performance, converts electricity supplies, or allows more than one device to plug into a single electrical power point. Common types of electronic or electrical adapters include:

  • Universal travel adapters
  • Voltage converters
  • DC/AC adapters
  • Headphone adapters and splitters
  • Bluetooth radio adapters
  • General plug adapters for different types of terminals (e.g., HDMI, micro/mini USB, lightning connector, etc.) 

Example sentences:

  • “The majority of modern-day audio players require a 3.5 mm input, but some gadgets still use other sizes that require an adapter to connect.”
  • “Universal adapters with built-in safety features can accommodate a variety of electrical appliances such as hairdryers, cell phones, and tablets.”
  • “You can charge lots of devices using an adapter that plugs in your car’s cigarette lighter.”
  • “She will need at least four different adapters for her digital camera in South America.”

Synonyms & related terms

Adapter/adaptor (mechanism)

Accessory, accouterment, addition, add-on, adjunct, appendage, appliance, attachment, auxiliary, clamp, connector, expansion board, expansion card, fitting, fixture, joint, link, supplement, option, part.

Adapter/adaptor (person or job)

Decoder, editor, explainer, glossator, linguist, polyglot, screenwriter, scriptwriter, translator.

Word history of adapter/adaptor

The noun adapter emerged around 1801 from the verb adapt (‘to modify, adjust’), stemming from Old French adapter via Latin adaptare (a form of adapto). Therefore, the initial definition of adapter was ‘one that adapts to something else,’ while subsequent usage involved chemical and mechanical adjustments before electrical engineering (c. 1907). 

Published examples of adaptor and adapter

“In the new Netflix series, the acclaimed adapter of works by Shirley Jackson and Stephen King tells a more personal story.” — The New York Times

“Lee Strasberg, a Polish émigré and the earliest adapter of Stanislavski’s techniques in the United States, embraced the simultaneously ominous and romantic undertones of this philosophy…” — The Atlantic

‘Whether it’s a reader, an illustrator or an adapter, I feel like, let a creative person take it in a direction they want to take it…’” — Los Angeles Times

“What fruit is hanging up there, in the top branches, awaiting the adaptor’s subtle hand?” — The Guardian

“… they visualized the spatiotemporal distribution of the phosphotyrosine-binding SH2 domains of various signaling and adaptor molecules in activated T cells…” — Science

“Depending on the degree to which a person uses the top and bottom systems in optional ways, he or she will operate in one of four cognitive modes: Mover, Perceiver, Stimulator and Adaptor.” — The Wall Street Journal

“The clamp band fixes the spacecraft to the launch adaptor and then releases in orbit, allowing the spacecraft to separate from the rocket.” — The Guardian

“It comes with a 3D-printed clip-on adapter that uses the camera’s flash to scan inside the eye and diagnose disease within 30 seconds.” — WIRED UK

“The Apple Lightning to USB adapter required to connect iOS devices is purchased separately.” — Forbes

Additional reading

If you enjoy learning about English grammar, be sure to check out similar lessons by The Word Counter, such as:

FAQ: Related to adaptor vs. adapter

What are universal travel adapters?

While this is not a grammar question, it’s worth mentioning for writers unaware of how to use the term “universal travel adapter” in contrast to any other type of adapter

In essence, universal travel adapters allow travelers to plug their electrical devices into wall outlets or power sources at various destinations. There are about 15 different design patterns for wall sockets worldwide, where individual metal plug inserts are called “pins” and “prongs.” 

Not all universal adapters accommodate every country, but most commercial products include flat, round, and rectangular two-prong and three-prong plugs with operative compatibility in North America, Europe, Asia, and South America.

Test Yourself!

Test how well you understand the difference between adapter and adaptor with the following multiple-choice questions. 

  1. True or false?: According to several different dictionaries, “adapter” is the only acceptable spelling of the noun. 
    a. True
    b. False
  2. True or false?: The spelling of “adapter” was once more common for British writers than American writers. 
    a. True
    b. False
  3. According to The Guardian’s internal style guide, the word adaptor is most suitable for referencing ____________.
    a. One who adapts a film script
    b. Phone chargers
    c. A mechanism that adapts different plugs
    d. USB ports
  4. Which of the following terms is related to an “adapter mechanism”?
    a. Glossator
    b. Polyglot
    c. Appendage
    d. All of the above
  5. The verb adapt derives from which two languages?
    a. Middle French and Latin
    b. Old French and Old High German
    c. Old French and Latin
    d. None of the above

Quiz Answers

  1. B
  2. B
  3. C
  4. C
  5. C


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  21. Photos by Doyoun Seo and Alexander Andrews on Unsplash.