'antineutrino' is formed from the prefix 'anti-' (from Greek 'ἀντί', meaning 'against' or 'opposite') + 'neutrino' (Italian diminutive of 'neutro', meaning 'neutral'), literally 'the opposite of neutrino'.

'neutrino' was coined in Italian by Enrico Fermi in the 1930s as a diminutive of 'neutro' ('little neutral one'); the English 'neutrino' was adopted soon after. The compound 'antineutrino' arose in physics literature to denote the antiparticle of the neutrino once particle–antiparticle theory and experimental evidence developed (mid-20th century).

Initially 'neutrino' meant 'little neutral one' (an Italian coinage referring to neutrality); over time the term came to denote the specific neutral, weakly interacting elementary particle we now call a neutrino, and 'antineutrino' came to mean its antiparticle with opposite lepton number.