Is the word invented a common noun?

No, the word "invented" is not a common noun. It's a past participle of the verb "invent".

Here's why:

* Common nouns are words that refer to general things or people (e.g., cat, chair, teacher).

* Past participles are verb forms that can be used as adjectives or parts of verb phrases.

Let's see how it works in a sentence:

* "The telephone was invented by Alexander Graham Bell." Here, "invented" describes the action of the telephone, making it an adjective.

If you want to use a common noun related to the concept of invention, you could say:

* "The invention of the telephone changed communication forever."