Subnotebook (also called an ultraportable, superportable or mini notebook) was a marketing term for laptop computers that are smaller and lighter than a typical 'notebook' sized laptop.

Types of subnotebooks, clockwise from left:
Classic subnotebook (Compaq Contura Aero),
Netbook (Asus Eee PC 1000H),
Palmtop/Handheld PC (Sony VAIO C1, Fujitsu Lifebook 810U)
Sizes (smallest to largest): Nintendo DS Lite (handheld), Asus Eee PC (netbook) and 13.3" MacBook (laptop).