Endor is the first planet in the Endor System. Endor is a silvery gas giant planet was the innermost world of the Endor System, located in the Moddell Sector near the area of Wild Space. Endor was orbited by nine moons, including the Forest Moon of Endor.
Endor was not located near any hyperspace node, and required a fairly complex series of jumps off the Sivestri Trace in order to get there. It was for this reason, coupled with the apparent lack of "intelligent life", that Emperor Palpatine chose to construct the second Death Star in orbit around the Forest Moon.
The Empire created the Sanctuary Pipeline in order to provide access to Endor for its supply ships, but this fell into disrepair after the Battle of Endor, once again cutting off most access to Endor.
Tana was the name used by the Ewoks to describe the gas giant of Endor, the primary world around which the Forest Moon of Endor orbited.