Sir John Cockcroft sir·john·cockc·roft uncommon noun 1. British physicist who (with Ernest Walton in 1931) first split an atom (1897-1967) SynonymsCockcroftSir John CockcroftSir John Douglas Cockcroft Related words Broader terms nuclear physicist WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.
