Coordinate vs. Cumulative Adjectives

In the previous lesson, we covered hyphens and dashes. Now, we're ready to move on to a tricky topic: coordinate vs. cumulative adjectives.

Coordinate adjectives individually modify a noun and are separated by a comma. For example, look at “heavy” and “bulky” in the following sentence:

• The heavy, bulky box was awkward to carry. 

You can tell that they're coordinate adjectives because they would still sound correct if you used “and” between them, such as:

• The heavy and bulky box was awkward to carry. 

or if you changed their order:

• The bulky, heavy box was awkward to carry. 

Also, if you have adjectives from the same category, such as two opinion adjectives or two size adjectives, you use a comma. For example:

• The beautiful, elegant box sat on the mantle. 
• The gigantic, enormous box was impossible to lift. 

Note that adjectives from the same category are rare in technical writing, as they’re mostly used to be emphatic. In tech writing, we aim to be precise but concise.

Cumulative adjectives are used when the adjectives are from different categories (e.g., age and size) or when the final adjective before the noun creates a compound noun. This is especially true when you specify origin (nationality/religion). For example, "and" sounds wrong between these adjectives, so you don't use a comma:

• Correct: She was a smart Muslim woman 
• Incorrect: She was a smart and Muslim woman 

But you could say “She was a smart and beautiful woman”, so these would be coordinate adjectives instead of cumulative:

• She was a smart, beautiful woman. 

Here comes the crazy part: cumulative adjectives must be in a specific order based on their category. This order is as follows, with examples for each category:

1. Opinion: good, attractive, delicious 
2. Size: large, small, enormous 
3. Age/Condition: old, new, modern, worn 
4. Length or shape: long, short, square 
5. Color: red, blue, green 
6. Origin (nationality, religion): American, Muslim 
7. Material: plastic, wooden, cotton 
8. Purpose: electric (wire), tennis (shirt) 

For example, these are in the correct order:

• An attractive young American lady 
• A modern Japanese electric car 
• A big square blue box 

But the following examples are NOT in the correct order and sound all wrong:

• An attractive American young lady 
• A Japanese modern electric car 
• A blue square big box 

This is hard to memorize, and it just takes practice. Most native English speakers have no idea that this order even exists; they just do it naturally and know something is wrong when they hear them out of order. I recently told a friend about this order and he laughed at me, refusing to believe this rule exists, until I started rearranging adjectives in a sentence. His eyes got wide, and he quickly changed the subject.

There are sites that show a much longer and more detailed list of categories, but it's simpler to stick with the more concise list above. In fact, if you search for "cumulative adjectives", you'll find a different list on most pages. I've chosen the list that I think covers the most important categories.

Summary

Coordinate adjectives are separated by a comma and sound fine if you change their order or insert "and" between them instead of a comma. Cumulative adjectives are not separated by a comma and must be placed in a specific order based on their category.

In the next lesson, we'll take a break from punctuation and talk about the essentials of technical writing.

Additional resources

http://wilcoxediting.com/articles/2009/04/07/comma-between-adjectives
https://www.khanacademy.org/humanities/grammar/parts-of-speech-the-modifier/adjective-order-and-commas-with-adjectives/v/commas-and-adjectives