'unequal-lobed' is a Modern English compound formed from 'unequal' + 'lobed'. 'unequal' itself comes from the negative prefix 'un-' (Old English/Proto-Germanic) combined with 'equal' (from Latin 'aequus' via Old French), where 'un-' meant 'not' and 'equal' meant 'even or level'; 'lobe' originates from Late Latin 'lobus' and Greek 'lobos', meaning 'a rounded projection', and 'lobed' is formed by adding the adjectival suffix '-ed' to 'lobe'.

'unequal-lobed' developed in Modern English by compounding the adjective 'unequal' and the participial adjective 'lobed' (from 'lobe'), building on earlier terms for 'unequal' in Middle English and for 'lobe' from Late Latin/Greek.

Originally words like 'lobed' were used simply to indicate the presence of lobes; in the compound 'unequal-lobed' the meaning specialized to indicate that the lobes are of unequal size or shape.