Coagulate
To cause to become a soft, semisolid mass, to curdle or clot. 

Coalesce 
To unite or merge. To grow together. 

Coal-fired Furnace 
Furnace that heats by burning coal as its fuel. 

Coal Tar 
Thick, black, opaque liquid, which is obtained by the destructive distillation of bituminous coal. Synthetic compounds such as dyes, medicines, explosives, perfumes, etc. have been developed from coal tar. 

Coarse 
Not fine or delicate in texture. Rough. Of inferior or poor quality. 

Coarse Aggregate 
Aggregate made up of coarse material, 1/4 inch and larger. 

Coarse Grain 
Wood grain with rings farther apart. 

Coarse Thread 
Machine screw that has a much smaller amount of threads per inch than a fine-thread screw, which has a larger amount. 

Coat 
Covering or layer of some substance. 

Coating In 
Painting a consistent coat onto a surface. 

Coaxial 
The installation of two or more objects so that their axes are the same. Cable in which a solid or stranded central conductor is surrounded by an insulating medium, which in turn is surrounded by a solid or braided outside conductor in the form of a cylindrical shell and is used for telephones, telegraphs, televisions, etc. Having a common axis. 

Co-brokerage 
Two or more authorized brokers who agree to cooperate together in representing a principal for the completion of a real estate sale. 

Cobalt 
A hard, lustrous, steel-gray, ductile metallic chemical element found in various ores. Metallic element: atomic number 27, atomic weight 58.933; atomic symbol Co. 

Cobble 
To pave with cobblestones.

Cobblestone 
Rounded stone used in paving streets or decoratively on walls or walkways. 

Cobweb Finish Paint 
Paint whose surface texture is similar in appearance to cobwebs. 

Cock 
1. A faucet or valve for regulating the flow of liquid or gas. 
2. To tilt or set jauntily on one side. 
3. The position a spring-loaded device to be put into action. 

Cockle 
A wrinkle or pucker. Depression in the surface of a piece of wallboard, done when being manufactured. 

Code 
1. An organized set of rules and regulation on a particular subject and are often an accumulation of laws in a particular area of interest. 
2. Identifying marking used on many items. 

Code of Ethics 
An organized group of ethical behavior guidelines, which govern the day-to-day activities of a profession or organization. 

Codicil 
An addition to a will, adding, subtracting or clarifying provisions of the document. 

Coefficient of Energy 
Actual rather than theoretical airflow, under set conditions, in an HVAC system. 

Coextrusion Welding
Welding process that combines both heat and extrusion on materials, which are to be welded through a die. 

Coffer 
1. Decorative sunken panel in a vault, dome, ceiling, etc. 
2. A chest or strongbox. 

Cofferdam 
A watertight, temporary structure, for keeping the water from an enclosed area that has been pumped dry so that construction may be done. 

Coffered Ceiling 
Ceiling which has sunken panels in a box-like structure. 

Cog 
1. One of a series of teeth on the rim of a wheel, for transmitting or receiving motion by fitting between the teeth of another wheel. 
2. A projection on a beam that fits into a corresponding groove or notch in another beam to make a joint. 

Cog Railway 
Railway used on steep inclines which consists of a gearwheel and cogged rail. 

Cognovit Clause 
Loan provision where a debtor authorizes a Judgment against him in the event of a default. These agreements are not lawful everywhere. 

Cogwheel 
Gearwheel.

Cohesion 
The tendency to stick together. 

Coign (also spelled Quoin) 
1. Building cornerstone or arch keystone. 
2. Building corner material, which is different from the rest of the wall, such as a block on a brick wall. 
3. Masonry unit finished on both its face and end. 
4. Right-angle masonry corner which projects from a wall. 

Coil 
1. To wind into a circular or spiral form. 
2. A spiral or loop of wire or other conducting element used as an inductor, heating element, etc. 
3. A helix.

Coil Spring 
Spiral of spring material. 

Co-insurance 
Coverage involving the use of two or more insurers. see coinsurance.

Coinsurance 
Policy that states the minimum percentage of value to be insured in order to collect the full amount of loss. Policyholders must buy insurance in an amount equal to the value of the improvements to their property. Arrangement where the insured and insurer share on a proportional basis the payment for a loss. 

Coinsurance Clause 
Provision in an insurance policy that "caps" the insurer's liability by stipulating that the owner of the property that has experienced damage must have another policy that covers usually 80% of the cash value of the property at the time of damage, in order to collect the full amount insured. 

Coke 
Coal from which most of the gases have been removed by heating. This industrial type fuel burns with little smoke and intense heat.