Here's why:
* Compound nouns are formed by combining two or more words to create a single noun (e.g., "fireplace," "high school," "toothbrush").
* Compound phrases are groups of words that function as a single unit, but the individual words retain their separate meanings. They are often used as a name for a particular sport, activity, or concept.
In this case, "track" and "field" refer to the distinct areas of competition within the sport.
Here are some other examples of compound phrases:
* "black and white"
* "up and down"
* "back and forth"
* "give and take"