The term is used predominantly in the United Kingdom, although some schools, mostly private, in other countries also use the title.
If there is more than one form for each year group they will normally be differentiated by letters (e.g., "3S" "Upper 4A", "Lower 2B", "10J", which may be written using Roman or Arabic numerals (e.g., "IIIS/3S", "UIVA/U4A", "LIIB/L2B").
In the past, British schools sometimes used a letter indicating a specialism, especially in 6th forms (e.g., "S" (Science 6th), "M" (Military 6th), "N" (Nursing 6th) or "T" (Teaching 6th).
"Forms" and their related terminology were widely used in school stories found in books, children's comics and other media in the 19th and 20th centuries.
The Luckiest Girl in the Fifth The works of Evelyn Smith e.g. Binkie of IIIB Billy Bunter - known as "The owl of the Remove" and his sister Bessie, created by Frank Richards; the Bunters appeared in comics, books, radio and television