Editing ISO 8601 (section)

===Ordinal dates===
{| class="infobox" style="text-align:center; width:23em"
| YYYY-DDD ||''or''|| YYYYDDD
|}

An ''[[ordinal date]]'' is an [[ordinal number|ordinal]] format for the multiples of a day elapsed since the start of year.
It is represented as "YYYY-DDD" (or YYYYDDD), where [YYYY] indicates a year and [DDD] is the "day of year", from 001 through 365 (366 in [[leap year]]s). For example, {{nowrap|"1981-04-05"}} is the same as {{nowrap|"1981-095"}}.

This simple form is preferable for occasions when the arbitrary nature of week and month definitions are more of an impediment than an aid, for instance, when comparing dates from different calendars. 
This format is used with simple hardware systems that have a need for a date system, but where including full calendar calculation software may be a significant nuisance. This system is sometimes referred to as "Julian Date", but this can cause confusion with the astronomical [[Julian day]], a sequential count of the number of days since day 0 beginning {{nowrap|1 January 4713 BC}} Greenwich noon, Julian proleptic calendar (or noon on ISO date {{nowrap|−4713-11-24}} which uses the Gregorian proleptic calendar with a year 0000).