Latinized form of Greek Κυνθία (Kynthia), which means "woman from Cynthus". This was an epithet of the Greek moon goddess Artemis, given because Cynthus was the mountain on Delos on which she and her twin brother Apollo were born. It was not used as a given name until the Renaissance, and it did not become common in the English-speaking world until the 19th century. It reached a peak of popularity in the United States in 1957 and has declined steadily since then.