Maemo OS - definition
Maemo is an open-source Linux-based operating system for smartphones and tablets, developed by Nokia and improved with community effort.
The Maemo OS was initially designed for Nokia Internet Tablets, a lineup which started in 2005 and ended in 2008 with the Nokia N810 WiMax edition. These internet tablets feature similar chipsets to Nokia's high-end N-series and E-series smartphones, but lack the telephony, have a landscape UI, which runs on 4.1-inch touchscreens with the relatively high resolution of 800 x 480px.
The last iteration of Maemo was called Maemo 5 and was featured on the Nokia N900, which was not marketed as an Internet tablet. It had a telephony functionality, a 3.5-inch screen and a slide-out keyboard. A portrait user interface was introduced for the first time.
In 2010 Nokia announced it will be merging the Maemo project with Intel's Moblin OS (another Linux-based open source mobile OS) to create a new OS, called MeeGo.