#mullion  a nonstructural vertical strip between the casements or panes of a window (or the panels of a screen)
  supertype:  strip.artifact__slip  artifact consisting of a narrow flat piece of material
  part of:  window  a framework of wood or metal that contains a glass windowpane and is built into a wall or roof to admit light or air
     part of:  edifice__building  a structure that has a roof and walls and stands more or less permanently in one place; "there was a three-story building on the corner"; "it was an imposing edifice"

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