1846, "of or like the nucleus of a cell," from nucleus + -ar, probably by influence of French nucléaire. Use in atomic physics is from 1914; of weapons, from 1945. Hence nuclear physics (1933), nuclear energy (1941), nuclear war (1954). Nuclear winter coined by Richard Turco, but first attested in article by Carl Sagan in "Parade" magazine, Oct. 30, 1983. General sense of "central" is from 1912. Nuclear family, originally a sociologists' term, is first attested 1949 in "Social Structure," by American anthropologist G.P. Murdock (1897-1985). Alternative adjective nucleal is recorded from 1840.
internuclear in·ter·nu·cle·ar (ĭn'tər-nōō'klē-ər, -nyōō'-)
Located or occurring between nuclei.
Located between nerve cell groups in the brain or retina.
nuclear nu·cle·ar (nōō'klē-ər, nyōō'-)
Of or forming a nucleus.
Of or relating to atomic nuclei.