Dictionary.net

• United States physicist and molecular biologist who helped develop the first atom bomb and later opposed the use of all nuclear weapons (1898-1964)

2006 - WordNet 3.0
By Princeton University

• United States physicist and molecular biologist who helped develop the first atom bomb and later opposed the use of all nuclear weapons (1898-1964)

2011 - English Dictionary Database
By DataStellar Co., Ltd