'apterium' originates from Modern Latin, specifically the word 'apterium', from Greek 'apteron', where 'a-' meant 'without' and 'pteron' meant 'wing' or 'feather'.

'apteron' (Greek) was taken into New/Modern Latin as 'apterium' for scientific usage, and from Modern Latin it was borrowed into English in technical/ornithological contexts.

Initially it meant 'without wings' (or 'wingless') in Greek compounds, but in modern biological usage it evolved into the specific meaning 'a featherless area on a bird's skin'.