'blue-green' originates from the combination of the words 'blue' and 'green', where 'blue' meant 'the color of the sky' and 'green' meant 'the color of grass'.

'blue-green' was used in Middle English as a descriptor for colors that were not distinctly blue or green, eventually becoming a recognized color term in modern English.

Initially, it meant 'a mix of blue and green', and this meaning has largely remained the same in modern usage.