The term 'Chamber Heart' refers to the four chambers of the human heart, which are the ATRIUM (6 letters), atrial (6 letters), and OVEN (4 letters). The ATRIUM is the upper chamber of the heart, which receives oxygenated blood from the lungs. The atrial is the lower chamber of the heart, which pumps the oxygenated blood out to the rest of the body. The OVEN is the middle chamber of the heart, which helps to regulate the flow of blood between the ATRIUM and the atrial. Together, these four chambers make up the chamber heart, which is responsible for pumping oxygenated blood throughout the body.