'anti-neutrino' is a compound formed from the prefix 'anti-' (from Greek 'anti' meaning 'against' or 'opposite') and 'neutrino' (Italian diminutive of 'neutro', meaning 'neutral'), so the term denotes the particle opposite to a neutrino.

'neutrino' was coined in Italian as a diminutive of 'neutro' ('neutral') in the early 20th century (popularized in physics by Enrico Fermi), and the English compound 'anti-neutrino' arose later as physicists named the corresponding antiparticle by combining 'anti-' with 'neutrino'.

Initially the element 'neutrino' meant 'little neutral one' (Italian usage), and when combined with 'anti-' the compound came to mean 'the antiparticle counterpart of the neutrino' in modern physics.