Eyeliner/ˈaɪlaɪnər/ Definition 1 of 1Pro Tip 1/3Cosmetic Product Eyeliner is used for makeup purposes to highlight the eyes. She loves using eyeliner when she gets ready for a party. Pro Tip 2/3Visual Impact Using eyeliner can change the perceived shape and size of the eyes. With eyeliner, her eyes appeared larger and more dramatic. Pro Tip 3/3Variety of Colors Eyeliner comes in various colors, not just black, to create different looks. She chose a blue eyeliner to match her dress.