Dates can also have the form @samp{@var{monthname} @var{day}} or
@samp{@var{monthname} @var{day}, @var{year}}, where the month's name can
-be spelled in full or abbreviated to three characters (with or without a
-period). Case is not significant.
+be spelled in full or abbreviated (with or without a period). The
+preferred abbreviations can be controlled using the variables
+@code{calendar-abbrev-length}, @code{calendar-month-abbrev-array}, and
+@code{calendar-day-abbrev-array}. The default is to use the first three
+letters of a name as its abbreviation. Case is not significant.
A date may be @dfn{generic}; that is, partially unspecified. Then the
entry applies to all dates that match the specification. If the date