What does a Julian date represent?

A Julian date represents the number of days that have elapsed since January 1st of a given year. This system of dating is used primarily in industries that require precise tracking of time and expiration dates, such as in healthcare and food production.

For example, if a Julian date is noted as "100", it indicates that it is the 100th day of the year, which corresponds to April 10th in a non-leap year. This numerical format simplifies date calculations and helps in managing time-sensitive materials, like sterile items in central services.

The other options do not accurately define a Julian date. The concept of the number of days until the end of the year, the total number of weeks in a year, or defining a specific month and day yields different meanings and does not fit the Julian dating system.