Meldrar I was the inhabited first planet in its star system. It was the location of a lunar prison where the temperature was two hundred degrees in the shade.
In 2370, Odo threatened to send Rom to Meldrar I for the murder of his brother Quark as a means to coercing Rom to tell Odo any information he might be withholding. (DS9: "Necessary Evil")
This planet was only mentioned in dialogue.
According to the script, the pronunciation for Meldrar was "MEHL-drahr".