Thrombocytosis is a medical condition where there is an increased number of platelets in the blood. There are several synonyms for thrombocytosis, including thrombocythemia, essential thrombocythemia, primary thrombocytosis, and myeloproliferative neoplasm. Thrombocythemia, like thrombocytosis, is characterized by an excessive number of platelets in the blood. Essential thrombocythemia is a rare blood disorder that can cause blood clots as a result of high platelet counts. Primary thrombocytosis is a chronic disease that can increase the risk of heart attack and stroke. Myeloproliferative neoplasm is a condition where there is overproduction of blood cells, including platelets. All these synonyms refer to a similar medical condition that requires proper diagnosis and treatment.