Comma Rule P: Put a Comma between Coordinate Adjectives.
Definition of Coordinate Adjectives. Adjectives are coordinate if they meet two criteria: (1) You can place and between the two words, and the sentence means the same thing, and (2) You can reverse their order, and the sentence means the same thing.
Sample 1: We had a hot, dry summer.
Sample 1 has the adjectives hot and dry, both used to describe summer. If we write We had a hot and dry summer, the sentence makes sense. It also makes sense if we write We had a dry, hot summer. The adjectives meet both criteria, so we know they are coordinate and put a comma between them.
To native English speakers, the two revised sentences will sound like natural speech, and the two criteria are likely sufficient to identify coordinate adjectives. For a more technical explanation, we can examine the Royal Order of Adjectives.
(If these criteria and revisions make sense to you, skip the next section and go to Rule Q.)
Definition of Royal Order of Adjectives. This is the order in which native English speakers naturally use adjectives in speech and writing. Although exceptions exist, such as to emphasize specific characteristics, this order is generally true.
The Royal Order of Adjectives is as follows.
1. Determiners: Words that indicate which one (e.g., this, the, a, my, her)
2. Observations: Subjective descriptions (e.g., fast, decrepit, easy, beautiful, inexpensive)
3. Size: Physical descriptions of size (e.g., large, small, huge, miniscule)
4. Shape: Physical descriptions of shape (e.g., round, square, lean, misshapen, long, oblong)
5. Age: Adjectives that indicate age (e.g., old, new, three-year-old, antique)
6. Color: Physical descriptions of color (e.g., red, blue, creamy, hazy, fuchsia)
7. Nationality: Originating location (e.g., American, French, European)
8. Material: What something is made of (e.g., silk, cardboard, rubber, sand, wooden, cream)
9. Type: The specific type of the thing (e.g., rocking [horse], digital [phone], acoustic [guitar]); may be considered part of the name of the thing described
The Royal Order of Adjectives indicates that The [determiner] black [color] sand [material] painting will sound natural but that The sand black painting will not. Similarly, Her [determiner] large [size] wooden [material] antique [type] clock will sound more natural than Her wooden antique large clock.
I don’t have this order memorized, but I don’t need to because I know what sounds natural.
The Royal Order of Adjectives is important to understanding coordinate adjectives. If you write two or more adjectives of the same type, they will be coordinate, and you will need a comma between them.
Sample 2: I have a fast, inexpensive car.
For example, fast and inexpensive are both observation adjectives. This means they are coordinate when used together, as in sample 2, and need a comma. We can also apply the two criteria to check this. We can put and between them: I have a fast and inexpensive car. We can reverse their order: I have an inexpensive, fast car.
Comma Rule Q: Leave out the Comma between Adjectives to Make Them Non-coordinate and to Change the Meaning
The comma between coordinate adjectives indicates that they both equally describe something. In sample 3, fast and inexpensive equally describe car. If you leave out the comma, however, you change the meaning of the sentence.
Sample 3. I have a fast inexpensive car.
In sample 3, you still indicate that inexpensive describes car, but you also indicate that fast describes inexpensive car. You tell the reader that your inexpensive car is fast. A fast inexpensive car is different than a slow inexpensive car, for example. The comma, or its absence, makes a lot of difference in your meaning.
If you’re using the Royal Order of Adjectives, you will see that when you leave out the comma, inexpensive becomes a type adjective, rather than an observation adjective. Inexpensive is a type of car in sample 3, making fast and inexpensive different types of adjectives, and you don’t need the comma.
I know this is getting confusing, so I’ll summarize the main points.
1) If the two adjectives equally describe something, they will meet the two criteria. Put a comma between them.
2) If the first adjective describes the next adjective and thing together, they won’t meet the two criteria. Don’t put a comma between them. This leads us to the following rule.
Comma Rule R: Don’t Place a Comma between Non-coordinate Adjectives.
Use the same two criteria to determine whether or not two adjectives are coordinate. If the adjectives don’t meet the criteria, don’t use a comma. This rule is, simply, the opposite of Rule P.
Sample 4: A large brown bear is loose in the park.
Look at sample 4. No comma is between large and brown. If we change their order, as in A brown large bear, it doesn’t make sense or, at the least, changes the meaning of the sentence. From this we know that these two adjectives are not coordinate, and we don’t put a comma between them. If we use the Royal Order of Adjectives, we also realize that these are different types of adjectives.
Sample 5: The original American flag is on display.
The two adjectives in sample 5 are not coordinate. We cannot write the American original flag or The original and American flag without changing the meaning of the sentence. Thus, the adjectives don’t pass both criteria, so we don’t put a comma between them.
If you’re using the Royal Order of Adjectives, you can see that these are different types of adjectives. Original is an observation adjective, and American is a nationality adjective. They are different types, so they don’t need a comma.
Comma Rule S: Don’t Put a Comma between an Adjective and the Thing It Describes.
Commas separate things. However, the adjectives should not be separated from the things they describe. For this reason, you don’t use a comma between the final adjective and the noun it describes, regardless of how many adjectives you use.
Sample 6: These old, red, wooden, frames are still my favorites.*
Surprisingly, this mistake is common, though it is so simple to avoid. If no words are between the adjectives and the word being described, you will never need a comma in that position.
In sample 6, for example, the adjectives are describing frames. No words are between the final adjective wooden and frames, so no comma should be there.
Need help with commas? Get Zen Comma, an instructive reference guide on the 17 major uses and misuses of commas.
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