The "978" in an ISBN stands for International Standard Book Number, which is a unique identifier for books. It is a 13-digit code which consists of three parts - the first 9 digits are the publisher identifier, the next digit is a code for the language and country of publication, and the final digit is a check digit.
For example, an ISBN starting with “978” will be an EAN-13 barcode, and the remaining 12 digits are an identifier used to identify a particular book.
The 978 in an ISBN is the beginning of the EAN-13 barcode standard which was devised by the International Organization for Standardization (ISO). Since this system was introduced in 2005, it has become the global standard for coding books.
The ISBN system has been in use since 1970, but the EAN-13 system has taken over and is now the global standard. The ISBN starting with 978 prefix is an EAN-13, and this prefix is used for all books that are printed after 2005.
Overall, the '978' in an ISBN stands for International Standard Book Number, and is the beginning of the EAN-13 barcode standard. This system has been put in place to uniquely identify and categorise books.
If you would like to learn more about ISBNs, you can read more about them here: https://thebookdesigner.com/what-is-an-isbn/