'partitionability' originates from Latin (via Old French and Middle English), specifically the Latin word 'partitio' or the verb root 'partire'/'partire-' meaning 'to divide' (with 'part-' meaning 'part'). The modern noun is formed by combining 'partition' + the adjective-forming suffix '-able' + the noun-forming suffix '-ity'.

'partitionability' developed from the Old French/Latin noun 'partition' (Old French 'particion', Latin 'partitio'), then English formed the adjective 'partitionable' from 'partition' + '-able', and finally the abstract noun 'partitionability' arose by adding '-ity' to the adjective.

Initially related words like 'partition' meant 'a dividing or portion', but over time the derived formation 'partitionability' came to mean specifically 'the property or capacity of being divided' rather than the act or result of dividing.