Pentath III was the inhabited third planet in the Pentath system. This was a Cardassian colony.
Pentath III was one of many planets in the Cardassian Union whose infrastructure was devastated by the Klingon invasion of 2372. An outbreak of Rudellian plague there prompted the Detapa Council to dispatch several relief convoys to the planet. Due to the lack of Cardassian fleet resources, the Council requested Starfleet escorts for the convoys. The USS Defiant was one of the starships assigned to this mission. (DS9: "Rules of Engagement")
This planet was only mentioned in dialogue.
This planet's quadrant of origin is inferred based on the position of the Cardassian Union as seen in the star chart appearing in the Star Trek: Picard episode "Maps and Legends".
According to the script, the pronunciation for Pentath was "PEN-tath". [1]