'externally-supported' originates from the combination of 'external' and 'support,' where 'external' comes from Latin 'externus' meaning 'outside,' and 'support' from Latin 'supportare' meaning 'to carry from below.'

'externus' transformed into the Old French word 'externe,' and 'supportare' became 'supporter' in Old French, eventually forming the modern English word 'externally-supported.'

Initially, it meant 'supported from the outside,' and this meaning has largely remained the same in modern usage.