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n. Deduction; specifically, in music, the regular succession of notes in the hexachords of the musical system introduced by Guido d'Arezzo, about a. d. 1024.

"Long before the birth of Jesus Christ, Roman custom drew a clear distinction between the sponsalia, or preliminaries, and the marriage itself, which latter culminated in the conducting of the bride to her husband's house (in domum deductio)."

deductio ad impossibile