Here are the ways "close" can be a noun:
* A near position or proximity: "The house is a close to the beach."
* A narrow escape or a call very near to winning: "The election was a close call."
* An end to a business deal or transaction: "We're nearing the close of the project."
However, "close" is much more commonly used as:
* An adjective: "The door is close."
* A verb: "Please close the door."
* An adverb: "She stood close to me."
So, while "close" can be a noun, it's not the primary way the word is used.