Definition: Haematology is a medical branch that deals with the study of blood, its cells (hematopoietic cells) and their functions. The word haematology comes from Greek "Haemat" meaning blood, "ologia" meaning study or knowledge and "logy" meaning science. The definition of "haematology" can be broadly described as the field that deals with the analysis and understanding of blood and its components. It includes aspects such as hematology (the study of the human body's blood supply), hematopathology (the study of disorders in blood vessels), haematological research (research into the biology and diseases associated with the circulation of blood), and haematobiology (the study of the functions of different blood types). Haematology is a vital field that helps scientists to understand how the human body's blood works, including its origin, composition and regulation. It also assists in developing new therapies for various conditions related to the circulatory system and can be applied in fields such as medicine, dentistry, pharmacology, genetic research, etc. The branch of haematology focuses on the analysis of blood cells (hematopoietic cells), their functions, and how they are regulated. This field also studies the diseases that occur in the circulatory system, including a variety of disorders that affect the heart, blood vessels, blood types, immune system, and more. Haematology is an important area that plays a vital role in medicine. It helps researchers to better understand the mechanisms behind various health conditions and aids in developing effective treatments for them.