Dual layer refers to a DVD recording technology that provides users with 8.5-GB of recording space (as opposed to 4.7GB of space) on a standard DVD+R discs). The additional recording space is the direct result of dual layer technology. As the name suggests, dual layer technology provides two individual recordable layers on a single sided DVD disc. To take advantage of dual layer technology when recording DVDs, you must use a dual layer enabled DVD burner and dual layer DVD media. Dual layer technology media can be read (once recorded) by most DVD drives and players currently on the market. Dual layer technology has been used for many years in the production of commercial DVD movies but is now available for home and business recording as well.
Dual Layer is more commonly called Double Layer in the consumer market, and can be seen written as DVD+R DL or DVD-R DL on recordable DVD media and hardware packaging.