from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A vertical member, as of stone or wood, dividing a window or other opening.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A vertical bar between the panes of glass or casements of a window or the panels of a screen.

from the GNU version of the Collaborative International Dictionary of English

  • n. A slender bar or pier which forms the division between the lights of windows, screens, etc.
  • n. An upright member of a framing. See stile.
  • transitive v. To furnish with mullions; to divide by mullions.

from The Century Dictionary and Cyclopedia

  • To form into divisions by the use of mullions.
  • n. In architecture:
  • n. One of the divisions between panels in wainscoting. Formerly monial.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a nonstructural vertical strip between the casements or panes of a window (or the panels of a screen)


from The American Heritage® Dictionary of the English Language, 4th Edition

Alteration of Middle English moniel, from Anglo-Norman moynel, perhaps from moienel, middle, from moien, from Latin mediānus, from medius.


  • Brick-clad columns and spandrel beams frame large, recessed storefront windows whose glazing is subdivided with elaborate mullion patterns.

    Georgetown's 'Social Safeway' is a monument to changing supermarket architecture

  • There are large "alfices" (rectangular ornamentation in the façade) enhancing the entrance, windows with small open spaces, separated by a small column-like mullion and multiple arches similar to the architecture found in Granada, Spain.

    The Meseta Purepecha

  • A recent visit to the house revealed that these corners must have finally failed or become too energy inefficient, as there was an additional mullion (black, I think) in place of each mitred corner.

    Question: Info on Architect Herb Fritz?

  • Each one is surrounded by hedges and a bluestone terrace with seating, and according to Cetra/Ruddy founding principal Nancy Ruddy, the "mullion-free glass" floor-to-ceiling windows create "an indoor/outdoor experience for residents using the space."

    Tishman Speyer Unveils Stuy Town Movie Theater, Library

  • Costume design: window mullion insertion and detailing

    Build Blog » BUILD 2008 Halloween Costumes

  • But, a multi-mullion dollar bridge to serve 400 people in Alaska that wipes out the natural habitat of thousands of animals will NEVER be a good thing in my mind.

    Think Progress » ThinkFast: April 20, 2006

  • The vertical line of the hay fork's middle prong rises almost dead center and is echoed in window's mullion, the house's lightning rod, its porch posts and siding and even in the seams of Papa's overalls.

    American Idol

  • A sitting room has a hand-painted ceiling frieze and a stone mullion fireplace.

    Lymington Luxury

  • In the mullion-windowed smoking-room, where men retired, and women too sometimes, into chairs old, soft, leathery, the ball of talk was lightly tossed, and naught so devastating as Foggartism mentioned.

    The Silver Spoon

  • He lay in a room with mullion windows, an ascetic room in a sixteenth-century house, close to the Cathedral, whose scent of age was tempered but imperfectly by the September air coming in.

    Maid in Waiting


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  • "This sluggish animal light that was baring the dormers and mullions and scullionsof Cold Comfort Farm"

    February 18, 2013

  • "1. In architecture: A division, typically of stone, between the lights of windows, screens, etc. Mullions were first used toward the close of the twelfth century, and reached their most perfect development about the middle of the thirteenth century. In the later medieval architecture, while becoming constantly more elaborate in design and in moldings, and exhibiting much science in the methods of assembling, the mullions are artistically less satisfactory in their lines. The word is in the plural almost synonymous with tracery. See also cuts under batement-light, geometric, decorated, flamboyant.

    2. One of the divisions between panels in wainscoting. Formerly monial.

    3. To form into divisions by the use of mullions."

    --Century Dictionary

    September 17, 2010