'reallocable' originates from Latin elements, specifically the prefix 're-' and the verb 'allocare', where 're-' meant 'again' and 'allocare' meant 'to place or assign'.

'reallocable' changed from the Latin verb 'allocare' (to place/assign) into Medieval/Late Latin and then into English as 'allocate'; the adjective-forming suffix '-able' (from Latin/Old French) produced 'allocable', and the prefix 're-' was added in modern English to form 'reallocable'.

Initially, 'allocare' meant 'to place' or 'to set in place', which evolved into 'allocate' meaning 'to assign for a purpose'; 'reallocable' has the current meaning 'capable of being reassigned or reallocated'.