'alidade' originates from Arabic, specifically the word 'al-ʿiḍāda,' where 'al-' meant 'the' and 'ʿiḍāda' meant 'instrument.'

'al-ʿiḍāda' transformed into the Medieval Latin word 'alhidada,' and eventually became the modern English word 'alidade.'

Initially, it meant 'instrument for sighting,' and this meaning has largely remained the same in modern usage.