This is the 2568th most frequent Chinese word.
紅色
"Red" (color).
This usage reflects '紅色' as an adjective describing the color of the noun 'flower' (花) to specify its attribute.
紅色的花聞起來很香。
The red flower smells lovely.
Here, '紅色' is again used as an adjective to describe the characteristic of the noun 'clothes' (衣服).
她喜歡穿紅色的衣服。
She likes to wear red clothes.
In this sentence, '紅色' operates as a predicate adjective, providing descriptive information about the subject 'national flag' (國旗).