'antinucleon' originates from the prefix 'anti-' (from Greek anti- meaning 'against' or 'opposite') combined with 'nucleon' (formed from Latin 'nucleus' meaning 'kernel, core' plus the particle-forming suffix '-on').

'antinucleon' was formed in Modern English in the mid-20th century by combining 'anti-' and the then-new scientific term 'nucleon' (itself coined from 'nucleus' + '-on'); it arose as particle physics identified antiparticles to nucleons such as the antiproton and antineutron.

Initially it was a straightforward coinage meaning 'the particle opposite to a nucleon'; this technical meaning has remained stable and specific to particle physics.