A door seems like a simple enough thing. Yet visit your local door showroom, and you may think the salesperson is speaking a foreign language. In a way, he is: It’s the arcane terminology of doors.
Most of us are familiar with that old residential standby, the hinged door. But other doors have less obvious names. The ones that slide into a hollow space in the wall are called pocket doors (not, as you might think, sliding doors).
Paired doors that slide past each other — often used for closets — aren’t called sliding doors either; they’re called bypassing doors. As a matter of fact, the only sliding door that’s actually called a sliding door is the glass kind that leads out to your patio.
Each individual door is called a leaf. Hence double doors are said to have two leaves; with the one that’s usually opened being called the active leaf. Those narrow pairs of doors that are hinged together in the middle — also common for closets — are called bifold doors. Doors that are split in half horizontally are called Dutch doors. Doors that swing in two directions are called double-acting doors.
Doors with glass in them, which most of us call French doors, are more properly called glazed doors. Each pane in a glazed door is called a lite, and the wooden bars dividing the lites are called muntins. Hence, the typical glazed door having one vertical muntin and four horizontal ones is called a 10-lite door.
Broadly speaking, there are two major styles of doors. The first, known as panel doors, were common from pre-Victorian times through the Depression, and were built of solid lumber enclosing varying numbers of recessed wooden panels. Designs ranged from six panels in Colonial-era homes to four in Victorian ones to a single large panel in homes of the inter war era.
Panel doors made a big comeback in the 1980s, though most are now just one-piece moldings made to mimic the real thing.
Modernist-era homes such as California ranchers, on the other hand, typically had doors with completely plain, flat surfaces. These are known as flush doors, and they can further be classed as hollow-core or solid-core, the latter being more durable and also more expensive.
Door hardware has its own arcane terminology. What most of us just call a doorknob is properly referred to as a lockset (the knob is just the visible part that turns). The direction a door opens is said to determine the "hand" of the lock: A door that’s hinged on the right and swings away from you, for example, is said to have a right-hand lock.
As for what you and I call hinges, door professionals rather inelegantly refer to them as "butts." To make things more confusing, butts are counted by pairs, not by the piece. Hence, a door with a hinge at the top and bottom is said to have a pair of butts, while a heavier door that requires three hinges is said to have one-and-a-half pairs of butts.
Listen, I just pass this stuff along — I don’t make it up.