diary-date

diary-date is a compiled Lisp function in `diary-lib.el'.

(diary-date MONTH DAY YEAR &optional MARK)

Specific date(s) diary entry.
Entry applies if date is MONTH, DAY, YEAR. Each parameter can be a
list of integers, `t' (meaning all values), or an integer. The order
of the input parameters changes according to `calendar-date-style'
(e.g. to DAY MONTH YEAR in the European style).

An optional parameter MARK specifies a face or single-character string
to use when highlighting the day in the calendar.