'two-nucleated' is a compound formed from 'two' (from Old English 'twā' / Proto-Germanic 'twai', meaning the numeral 2) and 'nucleated' (from Latin 'nucleus', meaning 'kernel' or 'core', via Neo-Latin/English formation 'nucleate' meaning 'having a nucleus').

'nucleus' originates in Classical Latin as 'nucleus' meaning 'kernel'; it passed into Neo-Latin and scientific English as 'nucleus'. The adjective 'nucleate' was formed from Neo-Latin 'nucleatus' and English '-ate' derivation, and the compound 'two-nucleated' was created in modern scientific English by combining the numeral element 'two-' with 'nucleated.'

Originally elements like 'nucleate' simply meant 'having a nucleus' (i.e., 'with a kernel'); the compound 'two-nucleated' now specifies the number, meaning specifically 'having two nuclei.'