Here's why:
* Compound nouns are formed by combining two or more words to create a new word with a single meaning. Examples include:
* sunrise (sun + rise)
* bedroom (bed + room)
* firefighter (fire + fighter)
* "Compound" is a single word with its own meaning, related to the concept of combining things.
However, "compound" can be used as part of a compound noun. For instance, you could have a "compound word", which refers to a noun formed by combining two or more words.