from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A standard paper size, defined by ISO 216 as having dimensions 74 x 53 mm (74.325 x 52.556 mm)
- n. Describing paper of that size.
- proper n. The eight former Eastern European countries that acceded to the European Union in 2004.
See the Wikipedia article on ISO 216, the international standard on paper sizes. (Wiktionary)