"Meckel's diverticulum" noun a diverticulum of the distal ileum, typically about 5 cm (2 inches) in length and located about one metre from the ileocaecal valve, present as a remnant of the proximal vitelline duct in some 3 per cent of individuals; an individual instance of this; (also) this structure regarded as a pathological condition (usually as the site of inflammation or haemorrhage).
"Meckel's diverticulitis" noun inflammation of Meckel's diverticulum.
"Meckel's cartilage" noun a cartilaginous rod or bar found in the mandibular arch of embryonic vertebrates.
Mid 19th century. From the name of Johann Friedrich Meckel the younger, German anatomist (grandson of J. F. Meckel the elder).