What is the meaning of Pantyliner?

A pad worn on the inner surface of women's underpants, up against the vulva, during a low-flow day of the menstrual period, designed to absorb small, spotty quantities of menstrual fluid, in contrast to a tampon or sanitary napkin, worn on heavy-flow days.

A similar product designed to absorb urine for women with light bladder leakage.

Source: wiktionary.org