Something that's sparkling shines or glints with many little lights. You might say that the starry night sky is sparkling.
You can describe someone's eyes as sparkling, if they twinkle with light, or admire the sparkling lights on your friend's Christmas tree. Another way to use the adjective sparkling is to describe a carbonated beverage, like sparkling wine or sparkling cider. Any fizzy, bubbly drink is sparkling. People have used sparkling to describe wine and eyes since the fifteenth century, and it comes from the Old English spearca, "glowing or fiery particle thrown off."