A world in the Star Trek universe. In the "TOS" (Kirk-era) timeline, it is in neutral territory between the Federation, Klingon, and Romulan governments. This was the site of the "Camp Khitomer" peace conference in which the Klingons and Federation began negotiating the peace that would be a major part of the Star Trek: The Next Generation mythos.
Years later the Klingons built an outpost on Khitomer. A traitor from the House of Duras gave up the outpost to the Romulans. Worf's parents were killed in the attack; he was rescued and raised by human Starfleet officers. This formative experience explains the character's decision to be the first Klingon to enlist in Starfleet, and his special regard for Romulans.