What is the noun form of seven?

There isn't a noun form of "seven" in the same way that "one" becomes "one" or "two" becomes "two."

However, you could use "seven" in a noun phrase, like:

* A group of seven (referring to a collection of seven people or things)

* The seven seas (a figurative phrase referring to all the oceans)

* The seven wonders of the world (a list of seven famous historical sites)

Let me know if you have another word you'd like to explore!