A mansard roof has two distinct slopes on all four sides. The upper portion is hipped, has a very low slope and is often not visible from the ground, while the lower portion is very steeply pitched and is often pierced by dormers. This type of roof got its name from the architect Francois Mansart, who popularized the design in France during the 1600s. In the United States, mansard roofs are generally a component of Second Empire style buildings, popular during the nineteenth century.
A mantel is the framework surrounding a fireplace. More elaborate versions are called a frontispiece or chimneypiece and may include a paneled section above the fireplace called an over-mantel. The woodwork surrounding a seventeenth, eighteenth or early nineteenth-century fireplace is an important indicator of its period of construction.
Moldings (also often spelled in its British version moulding) are decorative pieces added to structural elements (such as cornices, capitals, bases, door and window jambs, etc.) to introduce aesthetic variation. Traditionally of wood, moldings can have profiles that are curved, rectilinear or a combination of the two. Molding profiles in old and historic houses, found on decorative paneling, door and window surrounds and door panels can be an indication of the period of construction for these elements.
A mullion is a large vertical framing member (either of wood or stone) that separates multiple windows or panels of glass in a window. Mullions are often confused with muntins, which separate individual panes of glass in a window sash.
A muntin is the small wooden bar that divides a window sash into smaller divisions (which are called “lights”). By contrast, a mullion is a much larger bar, usually one that divides one window from another window in a group or row of windows (windows in groups of two or more are said to be mulled together, for example). Muntin profiles, their size and appearance may be useful as an indication of the period of construction for the window in which they are found.