The spindle checkpoint is a biological process that ensures the proper segregation of chromosomes during cell division. This checkpoint is essential in maintaining the genomic stability of organisms. Some synonyms for spindle checkpoint include mitotic checkpoint, spindle assembly checkpoint, and checkpoint control. These terms are all used to describe the same process that prevents cells from dividing until the spindle fibers are attached properly to the chromosomes. Other related terms include kinetochores, microtubules, and chromosomal instability. Understanding the spindle checkpoint is critical to developing treatments for diseases that result from chromosomal abnormalities, such as cancer and developmental disorders.