apologia

As you might expect, apologia is a close relative of apology. Both words derive from Late Latin; apologia came to English as a direct borrowing while apology traveled through Middle French. The Latin apologia derives from a combination of the Greek prefix apo-, meaning "away from," and the word logia, from Greek lógos, meaning "speech." In their earliest English uses, apologia and apology meant basically the same thing: a formal defense or justification of one's actions or opinions. Nowadays, however, the two are distinct. The modern apology generally involves an admission of wrongdoing and an expression of regret for past actions, while an apologia typically focuses on explaining, justifying, or making clear the grounds for some course of action, belief, or position.