Kelly green is a bright vibrant shade of green. The colour is basically a yellow-green and season spring. It is a vibrant colour that can be used for accents or for monochromatic effects. Kelly green is an American term. The name derived from the last name Kelly; a common last name from Ireland. The colour’s name was inspired by the bright emerald green hills of Ireland. The first time Kelly green was coined in the early 19th century and it stayed around ever since.