Dick Grayson was the original Robin, but when he decided he wanted to grow up, he graduated to Nightwing.
Even now, Dick is still young and when he first became Nightwing he was a Teen Titan. That look was hilariously of its time and he currently prefers red to turquoise (why DC why?!) but this is the costume I think of as Nightwing’s (it even showed up in the cartoon, remember?).