Why Doesn’t 'Explanation' Have an 'I' Like 'Explain'?

You use an explanation to explain something, so why does explain have an I but explanation does not? Grammar Girl explains.

Mignon Fogarty,
May 18, 2017


Every time I go to write explanation, I think it should have an I, like explain. You use an explanation to explain something, right? They should have the same root and be spelled the same way, right?

A Shared Root: Explanare

It turns out that explain and explanation do share the Latin root explanare, which means “to make clear,” “to smooth out,” and “to level.” 

And I’ll get to why the spellings are different in a minutes, but it turns out that explain has the kind of interesting changes in meaning that I find charming and like to share with you.

Going back to the 1500s, explain meant “to smooth out,” like talking about somebody unwrinkling his forehead: He must calm and explain his forehead

Later, it came to mean “to spread out or lay flat.” Here’s a sample from the 1673 book Some Opinions of Mr. Hobbs: ...as the tablecloth is explained upon the table? Or as butter is explained upon bread? This meaning also had a sense of making something visible. Maybe think of a map being spread out on a table and then the landscape becomes visible.

why explain has an I

In fact, explain is also related to the word plane--the tool for making wood flat and smooth. Cool, right?

Those meanings are now obscure, but I love how on your own (or at least on my own, I’ll speak for myself), I’d never think that explain would be related to words for “flat” or “smooth,” but then when I see the examples of how you can go from laying something flat and smoothing it out, to making something more visible, to making something more clear, to explaining, it all falls into place. 

Now, back to that pesky letter I.

A Wayward Son

The spelling of explane morphed over time to become explain, but explanation didn’t undergo the same transformation.

Think of it this way: Even though the words are like brothers, one of the two was more adventurous, going his own way in the world, while the more reserved son stayed home and took care of the farm. The Online Etymology Dictionary says explane changed its spelling because of the influence of the word plain. Apparently, even words can be corrupted by the influence of troublesome friends.

From now on, I’ll think of that I in the explain as a rebellious mohawk haircut meant to rankle explanation, the steadfast brother left behind.

Open the text for the next podcast segment in a new tab: How to Outline.


1. “explain.” Dictionary.com. Dictionary.com Unabridged. Random House, Inc.http://dictionary.reference.com/browse/explain (accessed: February 05, 2013).
2. “explain.” Dictionary.com. Online Etymology Dictionary. Douglas Harper, Historian. http://dictionary.reference.com/browse/explain (accessed: February 05, 2013).
2. “explain.”  Merriam-Webster Dictionary, online edition. http://www.merriam-webster.com/dictionary/explain (accessed February 5, 2013)
2. “explanation.” Dictionary.com. Dictionary.com Unabridged. Random House, Inc.http://dictionary.reference.com/browse/explanation (accessed: February 05, 2013).
3. “explanate.” Dictionary.com. Dictionary.com Unabridged. Random House, Inc.http://dictionary.reference.com/browse/explanate (accessed: February 05, 2013).

Explain photo from Shutterstock.

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