Agatha also Agata, is a feminine given name derived from the Greek feminine name Ἀγάθη (Agáthē; alternative form: Ἀγαθή Agathḗ), which is a nominalized form of ἀγαθή (agathḗ), i.e. the feminine form of the adjective ἀγαθός (agathós) “good”.. It was the name of St. Agatha of Sicily, a third-century Christian martyr.The name has been rarely used in English …