'well-proportioned' originates from the combination of 'well' and 'proportioned', where 'well' meant 'in a good or satisfactory way' and 'proportioned' referred to the relative size or extent of something.

'proportioned' changed from the Old French word 'proportioner' and eventually became the modern English word 'proportion'.

Initially, it meant 'having the correct or desirable relationship between parts', and this meaning has largely remained the same in modern usage.