'reactively-positioned' originates from the combination of 'reactive' and 'positioned'. 'Reactive' comes from Latin 'reactivus', meaning 'to act in response', and 'positioned' from Latin 'positio', meaning 'placement'.

'Reactive' evolved from the Latin 'reactivus' through Middle English, while 'positioned' evolved from the Latin 'positio'.

Initially, 'reactive' meant 'to act in response', and 'positioned' meant 'placement'. Together, they evolved to mean 'positioned in response to stimuli'.