'portend' originates from Latin, specifically the word 'portendere', where 'por-' (a variant of 'pro-') meant 'forward' and 'tendere' meant 'to stretch, to extend.'

'portend' changed from the Medieval Latin/Old French form 'portendere'/'portender' and via Middle English 'portenden' it eventually became the modern English word 'portend'.

Initially, it meant 'to stretch forward; to indicate beforehand', but over time it evolved into its current meaning of 'to be a sign of or to foreshadow (an event).'.