The term 'Swimming Unit' can be broken down into two parts: 'LAP' (3 letters) and the rest of the word. The term 'LAP' is a noun that refers to a single circuit of a swimming pool, lake, or other body of water. The rest of the term, 'Swimming Unit, ' is a unit of measurement used to measure the distance swum in a given amount of time. It is typically measured in meters and is used to track progress in swimming competitions.