A pantyliner is a very thin sanitary pad — a small soft strip that sticks inside the underwear. It is much thinner and smaller than a normal pad, because it is not made for heavy flow. Women use one on the light days at the start or end of a period, as a backup when using a tampon or a cup, or on ordinary days for everyday discharge and to keep underwear clean and fresh. That everyday use is the main one, and it is worth knowing, because a student who only learns "sanitary pad" will assume a pantyliner is just a smaller version of the same thing for the same days — it usually is not. The word is completely ordinary and not embarrassing: it is what is printed on the packet, what a shop assistant would say, what an advert says. You will see it written as one word, as two ("panty liner"), or with a hyphen; the packet spelling varies by brand. It is countable — one pantyliner, a pack of pantyliners.

護墊（衛生護墊）。就是超薄、平常日也可以用的那種，不是量多時用的衛生棉（衛生棉＝sanitary pad）。台灣包裝上寫「護墊」，講這個詞店員一聽就懂。