Flow is the volume of gases that pass through the system because of draft.

A flue is a duct, pipe, or opening in a chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors.

A damper is located in the flue of your chimney. The flue is where the smoke escapes when the fire is going. Dampers are placed inside of the flue to help control ventilation. Your damper should have a chain or handle that you can access in order to open and close it.

The ash dump door is located in the middle of the firebox and makes it easy to remove ash from the firebox. The dump door is opened to move the ash into the ash dump. The ash dump is the space directly below the ash dump door and is where the ash falls anytime the ash dump door is opened.

The smoke chamber is the area above the fireplace firebox (where you build your fire) just below the flue. This space is used to allow smoke to mix and curl in a circular motion and rise into the flue.

Your firebox is the part of your fireplace where the actual fire burns.

A fireplace hearth is the floor area within a fireplace.

The hearth extension is the noncombustible material in front of and at the sides of a fireplace opening. Hearths and hearth extensions are designed to prevent sparks from leaving the fireplace and igniting nearby combustibles.

Clearance is the distance that is considered to be safe between a heat-producing appliance, chimney, chimney liner, vent pipe, vent connector or other hot surfaces, and combustible materials.

There are spaces between the bricks of your chimney, and these spaces are filled with mortar

Creosote is actually just one of the components in the stuff (aside from the ash) that's left over when wood is burned. The whole mix of tar and creosote and soot is commonly called creosote.

The black residue left from burning material; a fine black powder that accumulates in chimneys.

Fireplace grates, typically made of steel or cast iron, increase air movement around the fire, allowing it to burn more evenly and efficiently

The lintel is a piece of steel that holds up the top row of bricks in the fireplace opening. It is used by the mason during installation of the fireplace to hold the bricks firmly in place until the mortar dries.

The chimney crown, which can also be referred to as a chimney wash, is a large slab that covers the top opening of the chimney. Unlike a chimney cap, which is typically made of metal and merely covers the opening to the flue, the chimney crown covers the entire top of the chimney.