German Baby Names Meaning: The name Agatha is a German Baby Names baby name. In German Baby Names the meaning of the name Agatha is: Good. Greek Baby Names Meaning: The name Agatha is a Greek Baby Names baby name. In Greek Baby Names the meaning of the name Agatha is: Good. St. Agatha was a 3rd century Christian martyr. Agatha was popular during the Middle ages. Famous bearer: twentieth Century British mystery writer Agatha Christie. Latin Baby Names Meaning: The name Agatha is a Latin Baby