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1. In private. This Italian phrase translates literally to "in the breast" in English. A: "Why did you want me to meet you in the basement?" B: "Because I have something important to tell you—in petto."
2. An Italian phrase used to describe the private appointment of cardinals by the pope. He was appointed by the pope in petto, which is why none of us knew about it.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.