Twelfth grade is the North American name for the final year of secondary school in most countries after which students usually graduate at age 18.
The twelfth grade is the twelfth school year after kindergarten. It is also the last year of compulsory secondary education, or "high school" in the U.S. Generally, students enter the grade as 17-years-old and graduate as 18-years-old.
Traditions associated with the senior year
Nearing the end of the school year, there is a graduation event where the graduating Seniors formally graduate from High School and receive their diplomas.
In most schools, seniors sit for formal senior portraits at the beginning of the school year or the summer prior to senior year. These portraits are used in the upcoming graduating class's yearbook. The senior portraits in the yearbook are often in full color and bigger than the smaller black and white pictures typically used for lower grades, some may even have a caption or a quote from the student.
Customarily there is a formal dance for this year's students, called senior prom. Some schools hold a combined prom for juniors and seniors, while others segregate the two grades into separate dances.
Senior skip day (also known as senior ditch day) is a day during which the seniors do not attend school and cut all their classes. This event/tradition is often not recognized by school administrations and teachers. In some areas it is countered with an officially recognized senior day off, or by allowing graduating seniors to skip their final examinations ("finals"). This official senior day can also be used to sponsor a "senior trip" where the graduating class would, for example, go to a theme park or some other vacation-type activity.
In some schools, Seniors receive a class ring at the beginning of their senior year. A Senior Prank is also another common tradition in which the class may contribute towards a practical joke on the school or administration.