'nuclear-conventional' is a compound formed by joining 'nuclear' and 'conventional'. 'nuclear' originates from Latin 'nucleus' meaning 'kernel, core', and 'conventional' originates from Latin 'conventio'/'convenire' (via Old French) meaning 'coming together' or 'agreement'.

'nuclear' changed from Latin 'nucleus' (Medieval Latin use: 'nucleus') into Modern English 'nuclear' via scientific usage; 'conventional' evolved from Latin 'conventio' through Old French 'conventioun' and Middle English 'convention' to the adjective 'conventional'. The compound formed in the 20th century as discussions contrasted 'nuclear' capabilities with 'conventional' ones, producing the hyphenated phrase.

Initially, 'nuclear' meant 'kernel' or 'core' and later came to mean 'relating to a nucleus' and, in the 20th century, 'relating to atomic energy or weapons.' 'Conventional' originally meant 'according to agreement' or 'customary' and evolved to mean 'ordinary' or, in military contexts, 'non-nuclear.' The compound now denotes the combination or contrast of those two categories.