Black Iron 
Iron without any finish on it, which is really gray-black in color. 

Black Walnut 
Hard brown wood normally used for making furniture.

Blade
The cutting part of a tool, instrument or weapon. 

Blade and Combination 
Combination square that has an attached center head which is able to slide along the blade of the square. 

Blade Load 
Material which is moved by a the blade of a bulldozer. 

Blanch 
To brighten by acid-cleaning. To bleach. 

Blanket 
Insulation batts. 40 to 100 feet lengths of insulation filled with fiberglass or mineral (rock) wool of some type. These blankets, known as rolls, are used when lengths of over 8 feet are needed. The blanket is cut to the size needed and secured to the framing by stapling flanges to it. Blankets come in various widths to fit 16" to 24" spans. Thicker blankets have higher R-ratings. Blankets come with a vapor barrier that is directed inside the house. If the blankets come unfaced, after they are in place, polyethelene sheeting is stapled to the studs. 

Blanket Insurance Policy 
Insurance policy covering multiple persons or pieces of property. 

Blanket Mortgage 
A mortgage covering more than one property owned by the same owner. 

Blast 
Air forced into a furnace under pressure. Sudden rise in pressure caused by an instantaneous release of energy. 

Blast Doors 
Doors that are specially designed and built to withstand or mitigate the pressure from a blast. 

Blast Furnace 
Furnace used for smelting iron ore. 

Blast Gates 
Adjustable sliding dampers used in a heating, ventilating and air conditioning (HVAC) to regulate air flow. 

Blasting 
1. Using explosives to break up or move rock and earth. 
2. Forcing a steady current of air into a blast furnace. 

Blasting Cap
The apparatus that contains the sensitive explosive charge, which is more easily ignited and powerful enough to be used to set off the main explosive charge. 

Bleach 
The use of chemicals to whiten or brighten. Any substance used for bleaching. 

Bleachers 
Bare benches in tiers without a roof, at sporting events. 

Bleed 
To come through a covering coat, as certain stains. To seep out. 

Bleeding 
The seeping or bleeding to the surface of a discoloration. Alternately, removing air by opening a valve at a high point in a hydraulic system. 

Blemish 
Defect which mars appearance. 

Blend 
To mix or mingle together. 

Blended Loan 
Mortgage refinancing in which the new interest rate takes into account the interest rate on the prior loan and the prevailing current market rate. 

Blended Rate 
Interest rate of a blended loan, which exceeds the rate on the old loan but is less than the rate on new loans. 

Blind Corner Cabinet 
Cabinet inserted into a corner with cabinets bordering it on both of the adjacent walls. Since access to a blind cabinet is limited, the installation of a lazy Susan section, with revolving shelves, improves its usefulness. Some blind cabinets are designed with faces at a 45 degree angle to aid function. 

Blind Dowel 
Used to join two pieces together, this dowel extends into holes joined in both pieces. The holes are not drilled completely through and the dowel cannot be seen once the joint is completed. 

Blind Header 
Brick header that is concealed. 

Blind Hole 
Hole that is not completely drilled through the material. 

Blind Joint 
Invisible joint. 

Blind Nailing 
Nailing in such a way to keep nail heads invisible on the finished surface. This is normally doe at the tongues of tongue-and-groove boards, such as strip flooring or done under roofing materials. The concealment, with putty, of nails that are driven into a wall. 

Blind Pool 
Limited partnership in which the specific properties are chosen by the general partner, after the funds become available. 

Blind Pool Syndicate 
Money raised by a promoter and placed into a fund prior to selection of investment properties. 

Blind Single Dovetail Joint 
Dovetail joint with the dovetail passing only part of the way through the other member. 

Blind Stop 
Stop for a storm window and/or screen that is a rectangular molding piece of the window frame. 

Blind Trust 
Appointing a fiduciary to manage finances and used in cases where a conflict of interest is possible. 

Blind Valley 
Valley that is added on to a roof slope that is already framed and sheathed. 

Blister 
Defect in paint that appears as a bubble under the surface, causing the paint to lift away from the surface underneath. Alternately, the portion of joint tape, which comes, unbonded from the surface of the joint. 

Block 
1. Rectangular area. 
2. Substantial number of real estate properties being sold together. 
3. Substantial amount of stock.
4. Building unit made of concrete with a nominal size of 8"x 8"x 16" and an actual size of 7 5/8" x 7 5/8" x 15 5/8 leaving the 3/8" to allow for a mortar joint.
5. Housing that has one or more pulleys.
6. Piece of wood used as a spacer.
7. Part of a subdivision or city divided by streets. 

Block and Tackle 
Mechanism made of one or more pulley blocks, with ropes or cables, for hoisting large, heavy objects. 

Block Bond 
Pattern of brick, in which all vertical joints are aligned because each course of stretcher is laid directly in line with the adjacent courses. 

Block Brazing 
Method of brazing, which derives the needed heat from, heated blocks adjacent to the parts being brazed. 

Block Bridging 
Use of wood the same size as the joist material for bridging, installed so that its vertical position is the same as the joists. 

Block, Load 
Crane hook assembly that with its frame, swivel, sheaves, pins and bearings suspended from its hoist ropes. 

Block, Long Type Load 
Crane hook is fixed on a trunion, which is attached to a housing with the sheaves mounted on the sheave pin. 

Block Plane 
Wood plane that is used to cut across the grain. 

Block Sequence 
Method of welding where layer of the weld metal are placed in an section which built up against the length of a weld area, with gaps left between the sections. The weld is finished by filling in the gaps with weld metal. 

Block, Short Type Load 
Crane hook and sheaves are mounted on the swivel for a short type load block. 

Block, Upper 
Sheave, bearing, pin and frame, which are located on a crane trolley, cross member to support the load block and load. 

Block Welding 
Weld material applied in layers along sections of the weld. 

Blockbusting 
The illegal act of inducing homeowners to sell their homes or properties by representing that persons of another race are entering the neighborhood. 

Blocking 
The installation of short boards between the joists, which strengthen a floor and keep the floor joists from twisting or bending, which would leave the floor unstable. This is also called bridging. 

Bloom 
Look of a semi-dry painted surface showing a multicolored hue. On masonry, it is the white, powdery deposits that are the soluble salts that have been dissolved by water and have moved to the surface. Repair of this requires that the powder be brushed off and the residue removed with a diluted solution of muriatic acid since it cannot be painted over. 

Blow 
The separation of layers in a plywood panel, usually caused by the buildup of steam pressure when the panel is being manufactured. Moisture with in the veneer, excessive glue spread or high press temperatures may be responsible for the steam. 

Blowdown 
1. Partial venting or draining, under pressure, of the water side of a boiler to remove or decrease unwanted contaminants. 
2. Pressure drop in a pressurized vessel from the opening of a safety relief valve to the resetting of the valve. 

Blown Oil 
Increased viscosity vegetable oil, saturated with air. 

Blown-in Insulation 
Insulation that is inserted into walls or other areas by being "blown in". Commonly used in attic floors or other areas that are inaccessible for normal installation, it can also be pumped into wall cavities through small openings in the sheathing. 

Blowpipe 
Soldering or brazing torch used in jewelry making or other work with fine joints because of its ability to be accurately directed due to its small flame. 

Blowtorch 
Torch used for soldering, activated by pressurized fuel and atmospheric air to generate its flame. 

Blue Lead 
Rust preventative made of lead sulfide and carbon. 

Blue Sky Laws 
State statutes that protect the public against securities frauds of real estate companies. These include regulations over the licensing of brokers, registrations, new securities and formal approvals by applicable government agencies. 

Blue Stain 
Discoloration of sapwood due to fungus. 

Blue Top 
Blue topped, wooden stake, which is used to mark for grading. 

Blueboard 
Water-resistant sheetrock which is commonly used in bathrooms. Blue paper covers it, giving it its name. 

Blued 
Finish, often given to unsold nails, which has a limited protective time. 

Blueprint 
Architectural plan used to build a home or other structure. 

Blue-ribbon Condition 
Also referred to as "mint" condition, this is an extremely well-kept house. 

Bluestone 
A variety of flagstone, used for paving, this blue, gray or green sandstone splits easily into thin slabs. 

Blunt 
Dull edged or thick. 

Blushing 
Whitened or cloudy defect on clear finished caused by excess humidity.