In geology, a mullion describes a linear, cylindrical structure comprised of elongated rods or columns 20 millimetres to 2 metres across and up, to 100 metres long.

The surface may be smooth or corrugated and define a lineation parallel to fold axes. Mullion structures are most common in strongly deformed metamorphic rocks, and may form by buckling of the surface between strong and weak rock beds.

Mul"lion (?), n. [A corruption of munnion, F. moignon stump of an amputated limb, stump, OF. moing mutilated; cf. Armor. mon, moun, mank, monk, and also L. mancus maimed.] Arch. (a)

A slender bar or pier which forms the division between the lights of windows, screens, etc.


An upright member of a framing. See Stile.


© Webster 1913.

Mul"lion, v. t.

To furnish with mullions; to divide by mullions.


© Webster 1913.

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