'unallocatable' originates from the prefix 'un-' meaning 'not' and the word 'allocatable', which comes from the Latin 'allocare', where 'ad-' meant 'to' and 'locare' meant 'to place'.

'allocare' transformed into the English word 'allocate', and eventually became 'allocatable' with the addition of the suffix '-able'. The prefix 'un-' was added to form 'unallocatable'.

Initially, 'allocare' meant 'to place or assign', and 'unallocatable' evolved to mean 'not able to be assigned'.