A tampon is a small firm roll of cotton or a similar soft material that a woman puts inside her body during her period, so the blood is soaked up on the inside instead of on a pad worn outside. It is the everyday word — there is no polite word and no rude word for it; a doctor, a shop worker and a teenager all say the same thing. Most have a string at one end so you can pull it out, and many come inside a plastic or cardboard tube (an applicator) that pushes it in. In shops you will see it as a countable noun (a tampon, two tampons, a box of tampons), and it goes with use, put in, take out, change: 'I need to change my tampon.' English speakers talk about this more openly than many people expect, but it is still a private-life word, so it belongs in talk with friends, family, a doctor or a shop assistant, not in a business meeting. In medicine the word is also used for a plug of cotton or gauze packed into any wound or opening to stop bleeding — this is where the word started, and a nurse may still use it that way. Rarer, and mostly a doctor's word, is the verb 'to tampon' a wound, meaning to plug it. Note also 'tamponade' (a related medical word about pressure inside the body), which sounds similar but is a different thing.