(1891-1986) a US diplomat (= person who represents his or her country abroad). He was the US ambassador (= senior government representative) to the Soviet Union (1943-6) and to Britain (1946). He was also the US Secretary of Commerce (1946-8) and governor of New York (1955-8). Harriman helped to carry out the Marshall Plan (1949-50) and to establish the Nuclear Test-Ban Treaty (1963). He was the main US representative at the Vietnam peace talks in Paris in 1968. His wife was Pamela Harriman.