What is the distance through the lower part of the shaft of a column, used as a standard measure for all parts of the order. See Module. Conjugate diameters. See under Conjugate called?

diameter — (Arch.) The distance through the lower part of the shaft of a column, used as a standard measure for all parts of the order. See Module. Conjugate diameters. See under Conjugate. (Webster's 1913.)

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