The term apologetics etymologically derives from the Classical Greek word apologia. In the Classical Greek legal system two key technical terms were employed: the prosecution delivered the kategoria (κατηγορία), and the defendant replied with an apologia. To deliver an apologia then meant making a formal speech or giving an explanation to reply and rebut the charges, as in the case of Socrates’ defense.
This Classical Greek term appears in the Koine (i.e. common) Greek of the New Testament. The Apostle Paul employs the term apologia in his trial speech to Festus and Agrippa when he says “I make my defense” (Acts 26:2). A cognate term appears in Paul’s Letter to the Philippians as he is “defending the gospel” (Philippians 1:7 & 16), and in 1 Peter 3:15 believers must be ready to give an “answer” for their faith. The word also appears in the negative in Romans 1:20: unbelievers are αναπολόγητοι (anapologētoi) (without excuse, defense, or apology) for rejecting the revelation of God in creation.