Basalt 
Dark, tough fine-grained to dense, extrusive volcanic rock, which commonly occurs in sheetlike lava flows. 

Bascule 
Device balance so that when one end is lowered, the other is raised. Hinged cantilever balance by a weight. 

Base 
1. Lowest part, bottom or first layer of a structure. 2. Chemicals with low PH that react with acids to form salts.

Base Cabinet 
Cabinets that are mounted or rest on the floor. 

Base Coat 
When multiples covering are planned, the first coat is the base coat. 

Base Course 
The bottom-most or first course in masonry. 

Base Leg 
Horizontal run length of a rafter. 

Base Level 
The level below which dry lands cannot be eroded. 

Base Loan Amount 
The total amount used to figure loan payments. If closing costs are financed, they are added to the base loan amount. 

Base Material 
Usually either gravel, concrete or asphalt, it is used in paving to compensate for ground movement, to provide drainage and to support the pavers. Material to form a place for welding, cutting or soldering to be performed. 

Base Metal 
Non-precious or structurally inferior metal. Metal to form a place for welding or brazing to be performed. 

Base Molding
Wood strip trim on the top of a baseboard, where it meets the wall. 

Base Ply 
Initial layer in a multi-layer system of the type of built-up roofing or a first layer of wallboard in a multi-ply construction. 

Base Rent 
Monthly fixed rental payment. 

Base Shoe 
Wood strip (molding) at the bottom of a baseboard to cover the gap between the baseboard and the floor, especially useful with an uneven floor. 

Baseboard 
Molding at the bottom of an interior wall, where the floor meets the wall. 

Baseboard Electric Heat 
Centrally controlled heating unit, installed along the floor. 

Baseline 
Reference line established for measurement taking. Horizontal line measured with special accuracy for survey with triangulation. 

Basement 
Below ground level area of a home or structure. 

Basin 
Wide, round shallow container for holding water. A sink or washbowl. Alternately, a depression in the dirt. 

Basin Wrench 
Wrench with a long handle that allows the jaws to reach and tighten nuts to fasten faucets to an already installed sink. 

Basis 
Value that is the starting point in computing gain or loss, depletion, amortization and depreciation. 

Basis Point 
Unit of measure for the change in interest rates. One basis point equates to one percent of one percent, 0.01. 

Basket Grip
Gripping mechanism in a cylindrical shape that slides over the end of a wire and holds it firmly in place while connecting to a fish tape. The wire is then pulled by the fish tape. 

Basket Pattern 
Masonry pattern of brick which gives the appearance of a woven basket by laying alternate sets of brick vertically, horizontally, vertically, horizontally, etc. 

Basket Strainer 
Basket-shaped strainer with holes and a slot that fits into the sink drain to allow water to run out but to catch food prior to entering the drain. 

Bastard File 
Coarse-toothed flat file which is used to remove a lot of stock but does not give a fine finish and requires a follow up with a finer toothed file. 

Bat 
Piece of brick with one end intact, which is used to fill in a section where only a partial brick will fit. 

Batch 
Amount of material mixed at one time; quantity of anything made in one operation. Grouping of a number of things or people. 

Batch Plant 
Production plant for large quantities of concrete. 

Bath 
Water or liquid used for washing a person or item. 

Bath, Receptor 
Small, low tub fashioned to be used as a tub for a child or a shower base. 

Bathroom 
Room with a bathtub, shower, toilet and sink. A half bath has only a toilet and sink.

Bathroom Accessories
Items manufactured for us in a bathroom, such as soap dishes, towel racks, etc. 

Bathtub 
Large plumbing fixture used for bathing an entire body. 

Bathtub, Recessed 
Tub that is enclosed on three sides by walls. 

Batt 
Piece of insulation that is pre-cut to fit between framing members. 

Batten 
Narrow strips of board used to hide joints between panels. In roofing, strips of wood used as the base for slate, clay tiles or wood shingles. For plastering, used as lath. 

Batten Plate Structural 
Steel plate, which is fastened to another member to add stiffness and strength. 

Batter 
Type of wall that is purposely built to slope on the outside even though it is straight on the inside. Also, masonry that slopes back in courses and is the reverse of a corbel. 

Batter Board 
Horizontal board nailed to posts set at the corners of an excavation to indicate the level wanted; fastening posts for stretched strings to indicate the outlines of foundation walls. 

Batter Brace 
Angled support that is close to the end of a truss. 

Battery 
Connected group of cells or a singular cell storing an electrical charge and capable of furnishing current. Alternately, a group of similar things arranged, connected or used together. 

Battery of Fixtures 
Plumbing fixtures all discharging into a common waste line. 

Battleships 
Metal strips that are used to fasten electrical switches and receptacles in old work where there is no other hardware to keep the box from falling out of the wall. Battleships are technically known as Madison clips but have a profile that resembles a battleship. 

Batts 
Precut lengths (four or eight feet) of insulation consisting of a filler of mineral wool or fiberglass and facings, one of which is a vapor barrier and flanges for nailing to the framing members such as studs or ceiling beams. 

Bauhaus Style 
Houses in this German style of architecture had no decoration and were smooth white blocks constructed of steel, reinforced concrete with integral walls of glass. 

Bay 
Space formed by the opening between two walls or columns. 

Bay Window 
Window, divided into three sections, that curves outward in an arc, extending the window area out from the wall, so that it gives a room a larger appearance. Since they are supported from the wall or floor and usually don't extend to the roof line, they need their own roof projection from the wall. Ready made bay windows come in pre-assembled components that are easily installed into a wall opening. Also called a bow window. 

Bay Window, Angle 
Multiple windows arrange to project from a wall. 

Baywood 
Mexican mahogany.