天蓝色用英语是 sky-blue。
解释：
sky-blue 英[skai blu:] 美[skaɪ blu]
adj. 天蓝色的，淡蓝色，蔚蓝色;
[例句]Her silk shirtdress was sky-blue, the colour of her eyes.
她一袭天蓝色的真丝衬衫式连身裙，和她的双眸颜色一样。
I was surrounded by sky-blue silk and polished lacquer.
我被天蓝色的绸子和光亮的漆器包围著。
We got into the sky-blue car, and left the parking lot.
我们坐进了那辆天蓝色的汽车，离开停车场。
She was wearing a pretty sky-blue dress.
她穿了一条漂亮的天监色裙子。
Product colors are: red, pink, orange, yellow, green, yellow-green, blue, sky-blue.
产品的颜色有：红色、粉红色、橙色、黄色、绿色、黄绿色、蓝色、天蓝色。
Sky-blue velvet breeches, fastened above the knee with diamond buckles;
天蓝色
天鹅绒的短裤，裤脚管到膝头上部为止，是用钻石纽扣扣紧了的。