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.
Definition of wall for English Language Learners : a structure of brick, stone, etc., that surrounds an area or separates one area from another : the structure that forms the side of a room or building