Tables consist of information arranged in rows and columns.
Keywords may be attached to both the Table as a whole or to specific columns and are used to specify additional information. Examples of keywords are revision number of a Table, author of the Table, units in a column, coordinate information for a column and so on. Keywords may also be used to store other Tables. One technical aspect of Tables that you should be aware of is that some Tables reference other Tables. We try to avoid making copies of Tables so that if two Tables contain almost the same data except for one or two columns, then a reference Table is created that points back to the original Table for shared information.