A more thorough explanation:

A certificate of correction is a document that is used to correct an error in an official document. For example, if there is a mistake in a certificate of incorporation, a certificate of correction can be used to fix it.

In the case of patents, a certificate of correction is issued by the U.S. Patent and Trademark Office when a patentee or assignee rectifies a minor error that is unrelated to questions of ownership or defects in a patent application's specifications or drawings.

There are three types of errors that a certificate of correction can correct:

1. Mistakes made by the PTO
2. Minor clerical or typographical errors
3. The omission or misidentification of an inventor's name

For example, if the PTO accidentally misspells the name of an inventor on a patent, a certificate of correction can be used to fix the mistake.