What are the categories of defects?

What are the categories of defects?

There are three main categories of defects:

1.    Wrong: The requirements have been implemented incorrectly. This defect is a variance from the given specification.

2.    Missing: There was a requirement given by the customer and it was not done. This is a variance from the specifications, an indication that a specification was not implemented, or a requirement of the customer was not noted properly.

3.    Extra: A requirement incorporated into the product that was not given by the end customer. This is always a variance from the specification, but may be an attribute desired by the user of the product. However, it is considered a defect because it's a variance from the existing requirements.