Tizen

Tizen is a Linux-based mobile, wearable and IoT OS developed by Samsung and backed by the Linux Foundation. It's based on Gentoo. The Linux Foundation started the Tizen project in 2011 as the successor to MeeGo. It was designed to use HTML5 apps and target mobile and embedded devices. Tizen 1.0 was released on April 30, 2012. In February 2013 Samsung merged their Bada operating system into Tizen 2.0, released on February 18, 2013.

Usage by Samsung
As of today, Samsung uses Tizen for its smartwatches (Galaxy Watch), as well as for their TVs.