A bedsore is a damaged, often painful place on the skin that appears when a person lies (or sits) in the same position for a long time. The skin and the flesh under it get squeezed; blood cannot move through well, and the place starts to break down. Nurses watch for them on the back, hips, heels, and tailbone of people who cannot turn themselves. It is a serious medical word you hear in hospitals, not a casual ‘I feel a bit sore.’ Though actually, the more exact name is pressure sore (or pressure ulcer), because you can get the same wound in a wheelchair, not only in bed — ‘bed’ is just how most people first meet it.