Commonly Confused Words

Plain and Plane

The words plain and plane are homophones. This means that they sound the same, but have different meanings.

Though both can be used to describe flat surfaces, they still don’t mean exactly the same thing when used in this way, as plain is used to describe geography, and plane is used to describe geometry.

This is the most common usage for the word plane. However it can also be used to mean glide.

The most common use of the word plain, is to be common, obvious, simple, or uncomplicated.

Rules to remember which to use in a sentence

I really struggled to find an overall rule for these words, and actually could only find one rule at all, so unfortunately, I have had to think of different rules for the different uses.

1. If you’re describing gliding, it’s plane you should use, as in aeroplane which also ends in the word plane.

2. If you’re trying to describe, or are referring to, a flat surface, and you don’t know which to use, think of this rhyme-

The train, rides across the plain.

Ask yourself – can the train, ride across the plain?

Or rather-

Is it land?

If the answer is yes it’s land, it’s plain you should use, which ends in the letters ain, as does the word plain.

If the answer is no, it’s not land, it’s plane you should use.

3. Otherwise (meaning, you are not describing gliding or a flat surface) it’s likely plain you should use. Unless you are referring to a level of existence, development or thought.