'nucleus-free' originates from Latin and Old English, specifically the words 'nucleus' (from Latin 'nucleus') and 'free' (from Old English 'frēo'), where 'nucleus' meant 'small nut; kernel' and 'frēo' meant 'free'.

'nucleus' came into English via Latin 'nucleus' (a diminutive of 'nux' meaning 'nut') and developed the figurative sense 'kernel' or 'central part'; 'free' descended from Old English 'frēo' meaning 'free'. The compound 'nucleus-free' is a modern English formation combining these elements to mean 'without a nucleus'.

Initially, 'nucleus' meant 'small nut' or 'kernel'; over time it came to mean the central part of a cell in biology, and 'nucleus-free' evolved to mean 'lacking that cellular nucleus'.