The following terms may be used throughout this section. Note that some glossary terms may be in italics throughout the section content but are not included in this list. A complete list of terms can be found in the Glossary. 

• adapter fitting: A fitting used to connect pipes with different connection types. (Section D-3.1)
• branch: The pipe that connects off the main run of a fitting. (Section D-3.1)
• bushing: A fitting used to reduce the size of a pipe opening, usually with threaded ends. (Section D-3.1)
• cap: A fitting used to close the end of a pipe with internal threads. (Section D-3.1)
• cleanout: An access point in a pipe system used to remove blockages. (Section D-3.1)
• coupling: A short fitting used to join two pipes in a straight line. (Section D-3.1)
• dwv fittings: Fittings used to carry drainage, waste, and vent fluids by gravity. (Section D-3.1)
• elastomeric: A material that is flexible and rubber-like, able to stretch and return to its original shape. (Section D-3.1)
• elbow: A fitting used to change the direction of a pipe. (Section D-3.1)
• full-face gasket: A gasket that covers the entire face of a flange, including the bolt holes, to provide a complete seal between two flanged surfaces. (Section D-3.2)
• gasket: (Sometimes referred to as a compression type fitting or connection); A flat sealing material placed between two surfaces to prevent leaks when they are joined together. (Section D-3.2)
• hub end: The end of a fitting that receives another pipe or fitting. (Section D-3.1)
• materials list: A list of materials needed to complete a job, used to communicate with suppliers or plan work on site. (Section D-3.3)
• materials takeoff (materials takeoff list): A detailed list of materials and quantities required for a job, often used for estimating costs and planning. (Section D-3.3)
• packing: A sealing material made of flexible (pliable) materials that provides a dynamic seal between a moving part and a stationary part, such as around a valve stem to prevent leaks. Common types include graphite packing. (Section D-3.2)
• plug: A fitting with external threads used to seal the end of a pipe. (Section D-3.1)
• plumber’s putty: A soft, moldable sealing compound used to create watertight seals around fixtures such as sinks and drains. (Section D-3.2)
• pressure fittings: Fittings designed to carry fluids under pressure.(Section D-3.1)
• reducing fitting: A fitting used to connect pipes of different sizes. (Section D-3.1)
• run: The straight-through portion of a fitting. (Section D-3.1)
• sanitary tee (san tee): A fitting used in drainage systems to connect pipes at a 90-degree angle with a curved path for smooth flow. (Section D-3.1)
• sealant: A material used to fill gaps and create a watertight or airtight seal between surfaces. (Section D-3.2)
• side inlet fitting: A fitting with an additional connection on the side. (Section D-3.1)
• silicone caulking: A flexible sealant and adhesive compound used to fill gaps and create a watertight seal around fixtures, joints, and surfaces, often containing mildew-resistant chemicals. (Section D-3.2)
• solvent cement: A chemical adhesive used to join plastic pipes by softening and fusing the surfaces together to form a permanent bond. (Section D-3.2)
• spigot end: The end of a pipe or fitting that fits into a hub end. (Section D-3.1)
• street elbow: An elbow with male threads on one end and female threads on the other. (Section D-3.1)
• tee: A fitting that connects three pipes. (Section D-3.1)
• teflon thread compound: A type of thread sealant that contains PTFE (Teflon) to help seal threaded connections, reduce friction, and prevent leaks. (Section D-3.2)
• thread compound (pipe dope): A paste applied to threaded pipe connections to seal gaps, prevent leaks, and make assembly easier. (Section D-3.2)
• union: A fitting that allows pipes to be easily connected and disconnected. (Section D-3.1)
• wye: A fitting that connects pipes at an angle (usually 45°) for smoother flow. (Section D-3.1)