Deus = God
Pater = Father
Deus + Pater = God the Father in Greek
Say "Deus" and "Pater" quickly enough and you will hear Jupiter, the supreme deity of the ancient Romans, who borrowed most of their gods from the Greeks. It may be easier to hear it if you change "Deus" to "Zeus." Now you know where that word came from.
Aren't I the life of the party? :)