The nucleolus organizer region is a specific area of the chromosome that is responsible for the production of ribosomes. This region is also known as NOR. Different synonyms have been given to this region of the chromosome, including nucleolar organizer region, nucleolar organizing region, nucleolus organizing region, and rDNA locus. These terms are often used interchangeably to describe the same region. The NOR region is essential for cell growth and replication, and any abnormality in this area can lead to genetic disorders. Therefore, understanding the various synonyms and terms used for the nucleolus organizer region is essential for anyone involved in genetics or medical research.