postnuclear

As a noun terms

is .

As an adjective postnuclear is

after the discovery of nuclear energy.

In linguistics|lang=en terms the difference between nucleus and postnuclear

is that nucleus is (linguistics) the central part of a syllable, most commonly a vowel while postnuclear is (linguistics) after the nucleus.

As a noun nucleus

is the core, central part (of something), round which others are assembled.

As an adjective postnuclear is

after the discovery of nuclear energy.