“Plane” and “plain” are a tricky word pair. These terms are pronounced the same but have different meanings. They also play different roles in a sentence, with “plane” primarily a noun and “plain” most often an adjective. Check out our guide to find out how to use these words correctly.
Plane (An Airplane, Flat Surface, or Tool)
The word “plane” has many uses, but the most common in everyday language may be as a shortened version of “airplane.” For instance:
We experienced no turbulence on our plane ride to Istanbul.
This abbreviated “airplane” is fine in less formal contexts, but you should use the full term in formal writing (e.g., essays or technical documents).
An “airplane” is so called because it flies flat through the air (at least, if everything is going to plan). And this sense of being flat or level points us to other uses of the noun “plane” you might encounter.
In mathematical terms, for instance, a “plane” is a flat surface:
The pool table surface is a single 4 X 8 ft plane covered in green baize.
Here, we use “plane” to show that the surface of the pool table is flat.
Another use of “plane” is for a carpenter’s tool. Appropriately, it is a tool used to create a flat surface. For example, we might say:
He used a plane to smooth the surface of the antique desk.
This, in fact, is the only case where “plane” can also be a verb:
He planed the surface of the antique desk.
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Here, for instance, “planed” means “used a plane to make something level.”
Plain (Simple or Ordinary)
“Plain” is mainly an adjective meaning “simple” or “ordinary.” For example:
She chose a plain wedding dress, free from any frills.
Here, we’re saying there’s nothing flashy or overly intricate about the dress.
Alternatively, we can use this word to mean “easy to understand”:
I’d be able to follow you more easily if you used plain English.
However, another common use for “plain” is as a noun. In this case, it is closer to the meaning of “plane,” as it refers to a large area of flat land. For example:
The city is located on a coastal plain, overlooking a natural bay.
But while “plane” can refer to any flat surface, the world “plain” is always reserved for a large, flat area of land.
Summary: Plane or Plain?
While “plane” and “plain” sound alike, they differ significantly in meaning:
Plane is a noun, often short for “airplane.” However, a “plane” can also be a flat surface or a tool used to create a smooth, flat surface.
Plain is an adjective meaning “simple,” “unadorned,” or “easy to understand.” However, it can also be a noun that refers to an area of flat land.
Hopefully, this has helped you understand how “plane” and “plain” work. But if you’d like an expert editor to help you make sure your writing is error free, try our proofreading services. Why not start with a free trial today?