Different types of data sources make use of similar concepts but refer to each differently. For example, the smallest meaningful element of data is called a field by many hierarchical database management systems and indexed data access methods, but called a column by relational database management systems.
There are other cases in which a common concept is identified by a number of different terms. For simplicity, we use a single set of standardized terms. For example, we usually refer to the smallest meaningful element of data as a field, regardless of the type of data source. However, when required for clarity, we use the term specific to a given data source. Each time we introduce a new standard term, we define it and compare it to equivalent terms used with different types of data sources.