This chapter provides medical terminologies in alphabetical order. Some of these terminologies include: abdomen; abscess; biliary colic; bacteria; biliary colic; brain stem; cancer; cardiology; concussion; digestive enzymes; echocardiography; gastrectomy; gastroenteritis; haemorrhage; immunization; jaundice; and Kveim test. Abdomen the lower trunk or the largest body cavity, which is situated in the trunk, immediately below the thorax from which it is separated by the diaphragm. Some strains of bacteria are parasitic on animals or plants, and can cause decomposition or disease as they multiply rapidly within the body, pathogenic bacteria associated with specific diseases. Gastrectomy operation performed to remove a gastric ulcer or tumour in the stomach, or to remove the entire stomach in cases of advanced cancer, gastroscopy visual inspection of the interior of the stomach using a gastroscope. Gastroenteritis inflammation of the stomach and intestines causing diarrhoea and vomiting.