Britain's largest and best-known aid agency (= a charity that helps people in poor countries). It was set up in 1942 (as the Oxford Committee for Famine Relief) to send food to people in other European countries. It now works mainly in developing countries, sending help when there is an emergency, and working with governments on projects to help poor people. Oxfam runs Oxfam shops in most British towns and cities, where new and second-hand clothes, books, etc. are sold to raise money for the charity. My shoes are new but everything else came from Oxfam.