What does regular decision deadline mean?

I'm planning my college applications and I keep seeing 'regular decision deadline.' I'm not entirely sure what this means for submissions and if late materials are accepted after this date. Could anyone clarify?

The Regular Decision deadline is the standard application due date at most colleges. Usually, this deadline falls in the beginning of January although it varies by school, some are as early as December and some as late as February.

When you apply Regular Decision, you submit your application by the deadline and colleges let you know their decision, typically by April. Regular Decision applicants then have until the national reply date, which is May 1, to commit to a college.

Late submissions are generally not accepted past the Regular Decision deadline, aside from certain extenuating circumstances and at the discretion of the college's admissions department. In order to be viewed as a competitive applicant, it's usually best to submit all materials by the stated deadline.

Additionally, schools may also allow for a grace period after the deadline for supporting materials (like recommendation letters or transcripts) to arrive, but this varies by school so it's something you should check on each school's admissions website.