Focal sclerosis is a medical condition, also known as focal segmental glomerulosclerosis (FSGS), in which the scarring of the kidney's tiny filtering units (glomeruli) leads to problems in urine filtration. There are a few other synonyms for focal sclerosis, including focal glomerular sclerosis, focal glomerulosclerosis, segmental glomerular sclerosis, and focal segmental glomerulosclerosis. While these terms represent the same condition, medical professionals and researchers may use them interchangeably, depending on their clinical or research context. Understanding these synonyms may help patients and their families to better communicate with their healthcare providers, as well as to learn more about their condition and available treatment options.