Lawrence Deems Egbert Sr., 80, an authority on international law, died Saturday at Sibley Memorial Hospital.

He was noted, in particular, for his work in connection with the Nuremberg war crimes trials and as compiler of a dictionary of legal terms.

Although he was an ardent pacifist, Dr. Egbert had served actively in both World Wars.

Born in St. Paul, Minn., he was a graduate of the University of Michigan. In World War I, he served with the navy as a signalman and then as a teacher of nautical astronomy.

Dr. Egbert took postgraduate work at Harvard University, attended the Academy of International Law at The Hague, and in 1926 received a state doctorate with highest honors from the University of Paris Law School.

He taught international law at the University of Illinois and Northwestern University, was an assistant to the law librarian of Congress, and from 1936 to 1941, was a specialist on commercial treaties and foreign commercial policies with the U.S. Tariff Commission.

In World War II, he was an officer with the Army Judge Advocate General's office and later served with the Normandy base section in France.

After the war, Dr. Egbert served for four years with the executive staff of the U.S. chief counsel at the Nuremberg trials. He was editor of the record of the trials and special translator to the late Justice Robert H. Jackson, then serving as U.S. chief counsel.

He compiled a Dictonary of Legal Terms in English, French, Spanish and Germn at the request of Justice jackson, "so that foreign lawyers may better comprehend each other and thus bring about greater understanding and hope if world peace."

During the past 12 years, Dr. Egbert revised and enlarged that dictionary with the collaboration of Dr. Fernando Morales-macedo, a World Bank terminologist. The manuscript at present is in the hands of publishers in this country and abroad.

Dr. Egbert was a reserch coodinator with the State Department from 1950 to 1960. he also served as a latin American specialist.

From 1963 to 1967, he was reserach director of the World Peace through Law Center. He was adjunct professor of international law at American University from 1949 to 1965.

He had been active for many years in the Inter-American bar Association, the Federal Bar Association, the American Society of International Law, the Interreligious Task Force on U.S. Food Policy, the United Nations of Washington and the Unitarian Association of America. He was a member of the Cosmos Club.

He is survived by his wife, Lyn, of the home in Chevy Chase; three sons, Dr. Lawrence D, Jr., Of Baltimore, John Paul, of McLean, and Charles F.D., of Washington; two sisters, Marguerite Scott, of Rochester, N.T., and jean Egbert, of Guilford, Conn., and nine grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Interreligious Task Force on U.S. Food Policy.