16.5 feet. The unit conversion and simplification commands will now
treat @code{rod} just like any other unit of length. You will also be
prompted for an optional English description of the unit, which will
-appear in the Units Table.
+appear in the Units Table. If you wish the definition of this unit to
+be displayed in a special way in the Units Table buffer (such as with an
+asterisk to indicate an approximate value), then you can call this
+command with an argument, @kbd{C-u u d}; you will then also be prompted
+for a string that will be used to display the definition.
@kindex u u
@pindex calc-undefine-unit