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.
Secondary cell walls. What is a primary cell wall. Growing plant cells are surrounded by a polysaccharide-rich primary wall. This wall is part of the apoplast which itself is largely self-contiguous and contains everything that is located between the plasma membrane and the cuticle. The primary wall and middle lamella account for most of the apoplast in growing tissue.