'nonarthropod' originates from Modern English as a compound of the prefix 'non-' and 'arthropod'. The prefix 'non-' comes from Latin 'non' meaning 'not', and 'arthropod' traces to Greek 'arthron' (joint) + 'pous/pod' (foot).

'arthropod' entered scientific usage via New Latin 'Arthropoda' from Greek elements 'arthron' and 'pous'; the English noun 'arthropod' developed from that scientific term. The negative compound 'nonarthropod' is a modern English formation using the prefix 'non-' + 'arthropod'.

Initially, 'arthropod' literally meant 'jointed foot' (from Greek) and referred to animals with jointed limbs; 'nonarthropod' has consistently meant 'not an arthropod' as a straightforward negation without major semantic shift.