Answering the question of "What did Grace Hopper discover in a computer?" will only highlight one of the many noteworthy achievements which she accomplished during her lifetime. If you ever heard of the term "debugging" it is because of Grace Hopper. After physically removing a moth from a computer, Grace Hopper was the first person to actually coin this term which we all use quite frequently to this day!

In the 1960's, Grace Hopper discovered Common Business-Oriented Language, otherwise known as COBOL. COBOL was one of the first programming languages to appear on the scene. This programming language is one that is still in wide usage today. Many of us have become a bit jaded about discoveries regarding computers, since new technology seems to appear every day. However, remember, we are talking about computers and their programming devices from over 40 years ago, when developments were not so rapid.
All computers use programming languages, as they help them to complete functions, perform calculations, and to create programs and interactions on the machine. COBOL is one that is primarily used for operations pertaining to administrative systems for governments and companies, businesses, and finance.
Grace Hopper lived from December 9, 1906 to January 1, 1992. In addition to being a computer scientist, she also achieved the rank of Rear Admiral in the United States Navy. Her achievements have been so broad, widespread, and significant, that people have called her "Amazing Grace."
In addition to her great achievements in the navy and with the Common Business-Oriented Language, she was also one of the first programmers of the Harvard Mark I computer.