Selective colleges seek to admit students that are highly interested in attending their college partly because their “ranking” is based on how many admitted students accept their offer. Most colleges have three “times of application.” Early Decision, Early Action, or Regular Decision.
Early Decision (ED) means you apply by early fall of 12th grade and receive an admissions decision the same fall. Students may apply ED to one college. To apply ED applicants are required to sign a binding contract that obligates them to attend the college if admitted. Applying ED can improve your probability of admission. The downside is you would not be able to compare financial awards from other colleges.
Early Action (EA) means students apply early in the fall of 12th grade and typically receive an admission decision the same fall. There is no binding contract so you may apply to as many colleges EA as you choose, but will typically not improve your probability of admission.
Regular Decision (RD) means students apply by late fall or early winter of 12th grade and receive an admissions decision in spring.