'reallocate' originates from Latin-derived prefix 're-' (meaning 'again') combined with 'allocate', which comes from Latin 'allocare' where 'ad-' meant 'to/toward' and 'locare' meant 'to place'.

'reallocate' was formed by adding the productive English prefix 're-' to the verb 'allocate' (from Latin 'allocare'); 'allocate' entered English via Middle French/Latin influence and became established in modern English as 'allocate' and then 'reallocate' developed to indicate doing allocation again.

Initially, components meant 'to place' ('locare') with the idea of assigning a place; over time 'allocate' came to mean 'assign or set apart', and 'reallocate' evolved to mean 'assign again or differently'.