'long-standing' originates from the combination of 'long' and 'standing', where 'long' meant 'extended duration' and 'standing' referred to 'existing or remaining'.

'long-standing' evolved from the Old English word 'lang' (meaning 'long') and 'standan' (meaning 'to stand'), eventually forming the modern English word 'long-standing'.

Initially, it meant 'existing for a long time', and this meaning has largely remained the same in modern usage.