noun: Initialism of time of flight. [(spectroscopy) The measurement of the time taken by an object, particle or wave to travel a distance through a medium.]
noun: (medicine) Initialism of tetralogy of Fallot. [(medicine) A congenital heart defect, characterised by the four findings of ventricular septal defect, pulmonary stenosis, right ventricular hypertrophy and an overriding aorta.]