Column 

All values in a column of a database table have the same data type. A value in a row of a column is the smallest data unit that can be selected from a table, to which functions can be applied, or that can be modified. Each column in a base table has a name that is unique within the table.

Column Types

Alphanumeric	Character string column All character strings in an alphanumeric column have the same length.
Numeric	Floating or fixed point column All numbers in a floating point column have the same coefficient length. All numbers in a fixed point column have the same format, that is, the same number of pre- and post-point decimal places.

See also:

SQL Reference Manual

Column Name

Defining columns with an SQL statement: column_definition