Is is a common noun?

"Is" is not a noun at all, it is a verb. It is the present tense form of the verb "to be."

Here's why "is" isn't a noun:

* Nouns name things, places, or ideas. For example, "dog," "park," or "freedom."

* Verbs describe actions or states of being. "Is" indicates a state of being.

Let me know if you'd like to know more about parts of speech!