Is a common or proper noun?

"Common" can be both a common noun and an adjective, depending on how it's used in a sentence.

Common Noun:

* When used as a noun: It refers to something that is ordinary or frequently encountered.

* Example: "The bird is a common sight in the park."

Adjective:

* When used as an adjective: It describes something that is ordinary, usual, or frequently found.

* Example: "That is a common mistake."

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