Wiktionary
n. makeup used to outline the the outer edge of the lips, generally to fill in uneven areas and create a smooth shape after applying lipstick.
Wikipedia
Lip liner, also known as lip pencil, is a cosmetic product. It is intended to fill uneven areas on the outer edges of the lips after applying lipstick, therefore giving a smooth shape. It is also used to outline the lips, keeping lipstick inside the lip area and preventing it from "bleeding", therefore creating a bigger contrast and making the lips stand out more. Alternatively, lip liner can be used to fill in the entire lip before the application of lipstick and in some cases, worn as a lipstick on its own. The product is usually sold in a retractable tube or pencil form which can be sharpened. Lip liner is usually available in the same range of colors as lipsticks: e.g., reds, pinks, browns, plums, etc. Lip liner also comes in invisible, for giving the illusion of smooth lips without adding or affecting color.
Usage examples of "lip liner".
She used dry eyeliner, liquid eyeliner, lip liner, lip conditioner, a frosted highlighter, and a pore minimizer.
A smooth, tawny-rose lip liner and gloss emphasized the sensuality of her mouth.
She spent more time than her impatience demanded on applying the tinted moisturizer, eye pencil, lip liner and lipstick she needed to feel good about herself.
But it was impossible not to notice him as she dabbed on foundation, powder, and blush and tried to put on lip liner with shaky fingers.
In the privacy of the security booth, she rummaged through her belongings and finally dropped a tin of aspirin, lip liner, and a ballpoint pen into the box.
No matter how ratty her sneakers, no matter how tatty her heels, no matter if her eye shadow had creases at the lids and her lip liner didn't match her lipstick, I'd sell her something fabulous and keep a smile on my face at the same time, even if I needed to rush into the employees' lounge and throw up afterward.
He had drawn on a beard with a red lip liner, and his left ear was covered with a bizarre bandage of gauze and surgical tape.
She had on more blue eye makeup than a seventies disco queen, and her lipstick was a shade redder than her lip liner.