resident – n. a doctor who is training at a hospital to become a specialist in a particular field of medicine

marathon – n. something (such as an event or activity) that lasts an extremely long time or that requires great effort

mobile phone – n. a small telephone that people can take with them and use outside their homes

fellowship – n. the position of a fellow at a university or college

potential – n. a chance or possibility that something will happen or exist in the future