Erythrocytolysin is a word used to describe a substance that is capable of destroying red blood cells in the body. Synonyms for this term include hemolysin, which is commonly used to describe any substance that causes the breakdown of red blood cells. Other synonyms that are less commonly used include erythrolysin, which specifically targets red blood cells, and cytotoxin, which can refer to any substance that causes cell death in the body. These terms are often used in medical research and discussions of diseases that involve the breakdown of red blood cells, such as hemolytic anemia.