A tuple is a fixed fixed-length list containing elements that need not have the same type. It can be, and often is, used as a key-value pair. A row (sometimes called a record) is the set of fields within a table that are relevant to a specific entity.
The stem wall on a concrete foundation is essentially the supporting wall that joins the foundation of a building to the vertical walls of the structure that is constructed atop the foundation.
Cell Wall. The cell wall is a tough, usually flexible but fairly rigid layer that surrounds the plant cells. It is located just outside the cell membrane and it provides the cells with structural support and protection. A major function of the cell wall is to act as a pressure vessel, preventing over-expansion when water enters the plant cells.