Intel's branding for a thin notebook computer that uses Intel CPUs, the Windows operating system and typically solid state disks (SSDs), especially in the lightest models. Introduced in 2011, Ultrabooks are widely available with 11", 13" and 14" screens and weigh from two to four pounds. They are the Windows equivalent to Apple's MacBooks.
Ultrabooks were the first to eliminate the optical drive to reduce thickness and weight. However, larger notebooks with optical drives were also sold under the Ultrabook banner. See solid state drive
, hybrid laptop
, convertible laptop
At three pounds, the 505G (top) was not called an Ultrabook in 1998, but it set the trend. With only a 2.1GB internal disk, it came with external floppy and CD-ROM drives. Today, Sony Ultrabooks (bottom) have up to 1TB of storage and are still just as light. (Images courtesy of Sony Corporation.)