What is meaning of rolling deadline of grad school application in US? I am applying for US grad schools and not finding a deadline on the website of certain schools. Instead, those websites say rolling deadline. I am confused what is meant by rolling deadline. Does it mean that applications are reviewed in the order they are received? If so, I am guessing this 'first come first serve' method would be unfair to a good applicant who apply relatively late and decisions are already made.
When there is a "rolling deadline" of any kind there is usually a "date of full consideration", or at least the earliest date the program will begin reviewing applications. Then the program will review applications as they come in, extending offers daily/weekly.

The program will continue to accept applications until a final close day is reached, or until they have filled all their available seats - whichever comes first. This is on contrast to programs that do not view any applications of any kind until the application date has passed, and then all applications are reviewed at once.

If you apply early to such a program, you may still be declined/rejected. However if you wait until too late then indeed if all seats are taken and the program is closed then you miss out on being considered, regardless of how good an applicant you were.

In such a system you are generally best to get in your application as close to the first review date when applications open. In the job world this is analogous to job postings that list "until position is filled", and basically work the same way.