There are 3 types of applications: Early Action, Early Decision, and Regular Admissions, and Rolling Admissions
And 4 types of admissions decisions: acceptance, waitlist, deferral, and denial.
Understanding these terms will help you during your application process.
Most early action applications end by Nov. 1. With these, a student applies early and can recieve an admission decision sooner. Students can apply for multiple schools early and have until May 1st to review offer letters before accepting a college's offer. Applying through early action is always a great option for competitive schools. This helps reduce the chance of a student being waitlisted (meaning they're accepted but they can't attend unless other students ahead of them do not go to that college).
Students can only apply Early Decision to one college because it is binding. If accepted by an Early Decision admission decision a student is expected to enroll at that college, regardless of what other colleges may offer. Students are also expected to withdraw all other applications if accepted by early decision. The appeal to applying for college using early decision applications is that it demonstrates a student's interest in the school. That said, students should only do early decision if: the college is their number 1 choice, the student is certain of their financial aid offerings and how they'll afford college, and the student has consulted members of their support group (counsellor's, advisers, coaches, family, etc). These applications typically close on Nov. 1.
Applying for regular admissions is the most common path. This provides the benefit of extra time to take tests and secure recommendation letters. When it comes to more competitive schools, a student may be waitlisted if they wait too long to apply. The student may also have less financial aid (especially needs-based aid) since a lot of aid is first come, first served.
Some schools accept applications until the first day of classes, these are rolling admissions schools. This allows applicants to have more flexibility and are most common for non-competitive programs. Students should still apply as soon as possible to rolling admission schools to have the best chance of receiving aid and avoid waitlisting.
An admitted student was accepted by the institution and can attend as long as they complete their next steps these include: making an institution email address, registering for classes, attending a freshman advising session, completing freshman orientation, and sending a non-refundable deposit (unless a student gets this waived). A student should compare all financial aid offers from the schools that admit them before deciding.
The student's application was rejected by the college and they cannot attend that admissions cycle (some schools/programs allow applications each semester and some only admit annually).
Only students with Early Action and Early Decision applications may see a "deferred" decision. This means that the college is not ready to admit/deny based on the current application. This decision allows the student to join the regular application pool. The college may ask you to send additional materials if this happens.
Being waitlisted means that a student was accepted. However, the institution accepted more students than they had available seats. Waitlisted students will not be able to attend an institution unless people that were accepted before them choose to not go (or fail to make their deposit).
Once a student has decided on the college they'll attend, they'll have to accept the college's offer. This usually involves sending a non-refundable deposit (usually under $1,000). This deposit can be waived through the institution (if the financial aid office has waivers) by filling out and sending a NACAC Fee Waiver form.
Make sure to attend freshman orientation, meet with an academic adviser, financial aid, and complete all the other steps needed to enroll as soon as possible. The sooner you register for classes, the more options you'll have.