A more thorough explanation:

An Assistant Commissioner for Patents is a high-ranking official in the U.S. Patent and Trademark Office who assists the Commissioner for Patents in overseeing the patents section of the office. The Commissioner for Patents is the chief operating officer of the patents section and is appointed by the Secretary of Commerce.

Other types of commissioners include:

• Commissioner for Trademarks: The chief operating officer of the trademarks section of the U.S. Patent and Trademark Office.
• Commissioner in Bankruptcy: An English law commissioner appointed by the Lord Chancellor to proceed in corporate-bankruptcy cases.
• Commissioner of Deeds: An officer authorized by a state to take acknowledgments of deeds and other papers while residing in another state.
• County Commissioner: A county officer charged with managing the county's financial affairs, its police regulations, and its corporate business.

For example, a County Commissioner may be responsible for managing the budget for a county's police department and overseeing the construction of new roads. Similarly, a Commissioner of Deeds may be authorized to take acknowledgments of deeds for a state while residing in another state, making it easier for people to complete legal transactions across state lines.