Rhymus Major was a planet located in a binary star system.

Quark's first holosuite program was set on this planet, including a picnic, waterfalls, flitterbirds, and Mordian butterflies. He once enjoyed this program together with Natima Lang and still owned it in 2370. (DS9: "Profit and Loss")

This planet was only mentioned in writing.
Both and the Star Trek Encyclopedia (4th ed., vol. 2, p. 221) located Rhymus Major in the Rhymus system. This system was described by the former as having at least two planets, with one of them being class M.