Erythroid refers to anything that relates to or is involved in the formation or function of red blood cells. Synonyms for the word erythroid can vary depending on the context in which it is being used. Some possible synonyms include hemopoietic, hematopoietic, red cell, haematopoietic, and hematogenic. These terms are all related to the process of blood cell development and can be used interchangeably with erythroid in certain situations. Additionally, other words such as blood-forming, red bone marrow, and erythropoietin can also be used to describe processes or substances related to the formation of red blood cells.