fifteener

plural fifteeners

1. UKinformalA film assigned an age rating of 15, those under 15 not being permitted to view it.

   Not intensely bloody decapitation, but the sort of violence you'd see in a fifteener.

   2009 January 24, Interviews by Becky Barnicoat, “Good to meet you: The Jackson children”, in The Guardian

2. informalbibliographyA book or other printed item that was printed in the 15th century (thus, during the first half-century of printing).

   1 more example

   When here and there throughout those volumes you meet with titles of books now either unknown entirely or of the greatest rarity; when you find the Colophon from the end or the "insignum typographi" from the first leaf of a rare "fifteener" pasted down with dozens of others varying in value, you cannot bless the memory of the antiquarian shoemaker, John Bagford.

   1880, William Blades, The Enemies of Books, page 97

   Synonyms: incunabulum, incunable