This document discusses key concepts in the Microsoft Dynamics AX 2009 data dictionary including MorphX, the Application Object Tree (AOT), opening the AOT, tables, data types, extended data types, base enumerations, and views. The AOT is a tree view of all application objects that allows developers to design objects like tables, forms and reports. Tables store company data and transactions, and have fields, indexes, and relations that define them. Data types include primitive types like strings and integers as well as extended types that can inherit properties. Base enumerations provide predefined values for enum fields, and views are virtual tables that retrieve specified data.