Grammar Adapter vs. Adaptor: Is There a Difference? |
The Blue Book of Grammar and Punctuation

Adapter vs. Adaptor: Is There a Difference?

One of many things that make the English language both fascinating and perhaps confusing is that it always evolves over time and across regions. Because of that, there can be subtle differences in English usage and expression from one place or era to the next. That can sometimes create uncertainty about spelling, usage, and interpretation.

Today’s topic wades into one of those gray areas. We will look at the difference between adapter and adaptor so you can determine which word to apply in your writing.

The Difference Between Adapter and Adaptor

You have likely come across the words adapter and adaptor. You may also have wondered about their meanings or origins: Are they similar or separate?

Both versions of the word are nouns that refer to the same thing: a person or object that brings separate qualities together. For example, you are probably familiar with an adapter that connects a device to your computer. You might also have used an electrical adapter that enables your electronics to work in different countries with their own voltage requirements.

The difference between adapter and adaptor is really just a simple matter of spelling. The -er version tends to be preferred in the U.S., while the -or version is more common in the U.K.

As with so many parts of our language, the word adapter has adjusted as it has moved from one setting to another. Therefore, you’ll typically find it spelled and pronounced one way in America and another way in Commonwealth countries. That difference alone isn’t usually great enough to cause confusion.

One Minor Adapter vs. Adaptor Wrinkle

Some people might think these two words have separate meanings determined by their spelling. The idea is that one version applies to a person who is serving as an adapter and the other refers to an object acting as an adaptor (such as for power conversion).

This distinction sounds reasonable, and such a minor variation wouldn’t be unusual in English. However, there doesn’t seem to be any history or documentation to support this division of uses. If there ever was a difference between adapter and adaptor (which seems unlikely), it has disappeared over time.

How to Use Adapter and Adaptor Correctly

Since the two words share the same meaning, it’s best to use adapter in the U.S. and adaptor in the U.K. If you have a preference for one over the other, or you follow a style guide with its own established direction, you would be fine to use either word as you wish. Simply remember that adapter and adaptor mean the same thing and are pronounced the same way.

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3 responses to “Adapter vs. Adaptor: Is There a Difference?”

  1. Sharon says:

    Is this the same for adviser and advisor?

    • GrammarBook.com says:

      “Adviser” and “advisor” are both accepted spellings of the same word. Neither seems to be a preferred spelling over the other in the U.S. or the U.K.

  2. Richard says:

    Adaptor changes form, e.g., a plastic to rubber hose adapter. Adapter changes function, e.g., a 120 volt AC to 5 volt DC phone charger or a unit that converts a vacuum to a shampooer. This is the engineering etymology of the term “form over function,” so the spelling is accurate. I thought everybody was taught this like “I before except after c or when sounded in a as in neighbor or weigh.”

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