Faucet (tap)The valve fitting that brings hot and cold water to the bowl. Faucet is the usual word in the United States and tap is the British one. A top mount faucet fits through holes in the top of the sink.
Basin (bowl)It is the fixture itself. Stainless steel is the most common choice in kitchens, and porcelain, cast iron, fireclay, copper and stone are all used. The trade calls a bathroom sink a lavatory.
Supply lineA connector carrying water from the stop valve up to the faucet. One for hot and one for cold. Flexible ones are braided stainless steel or vinyl. Rigid chrome-finished copper ones are called risers.
Shutoff valve (angle stop)It shuts off water to this one fixture. The one drawn is an angle stop: water comes level out of the wall and leaves upward, at 90 degrees. A straight stop sits on a pipe that comes up through the floor. There are two, hot and cold.
TailpieceThe first pipe under the drain, leading straight down to the trap. Bathroom sinks take 1-1/4 inch tubular parts and kitchen sinks 1-1/2 inch. A branch tailpiece has a side nipple for a dishwasher hose.
J-bend of the P-trapThe curved piece shaped like the letter J. With the wall tube it makes the P-trap, which is named for its shape. One maker says a worn one is the most common cause of a leak under a sink.
Pop-up stopperThe plug of a pop-up drain. It moves up to let water out and down to hold it, worked from the faucet and not by hand. A hole near the end of its tail catches the tip of the pivot rod.
The whole sink 10
HandleIt opens and closes a valve inside the faucet. In the United States the hot one is on the left. This side view hides the second one behind the first. A single lever moves up and down for flow and side to side for temperature.
SpoutThe outlet tube of the faucet. One maker's glossary lists it with the handles as faucet trim, the decorative parts you can see. In a mixer faucet, hot and cold are blended before they reach it.
AeratorIt draws air into the stream, which cuts splashing and limits flow. Its three main pieces are a housing, an insert and a rubber washer. Bathroom faucets with the U.S. WaterSense label use at most 1.5 gallons per minute.
Lift rodPull it up and the stopper drops to hold water. Push it down and the stopper rises. It passes down through the faucet and the counter to the linkage under the sink.
Rim (flood level rim)The top edge of the bowl. Plumbing references call it the flood level rim: the edge from which water would overflow. The air gap that keeps a faucet outlet clear of dirty water is measured down to it.
OverflowAn opening near the top of the bowl. It leads through a hidden channel to portholes in the side of the drain body. If the drain is plugged and the water keeps running, this is the way out.
Slip nutIt makes a slip joint. One tube telescopes into the next, and the nut squeezes a washer around the inner tube to seal it. Plastic ones are tightened by hand only. The drawing has two, one at each end of the J-bend.
Water seal (trap seal)Water that stays in the bend after every use. It blocks sewer gas from rising into the room. It is usually about 2 inches deep, measured up to the weir, the point where water spills over into the wall tube.
Wall tube (wall bend)The outlet half of the P-trap. An elbow and a level run carry waste from the J-bend to the drain pipe in the wall. It is cut to length when the trap is fitted.
EscutcheonA trim plate where a pipe passes through a rough hole. It bridges the gap between them. The same word names the plate around a keyhole.
Drain close-up 5
Drain flangeThe finished ring at the top of the drain. The only piece of it seen from above. A circle of plumber's putty under its lip seals it to the bowl. Regular putty is oil-based and can stain granite or marble.
Rubber gasketA soft ring on the drain body, under the bowl. Tightening the locknut presses it up until it is firmly seated, and that makes the seal on the underside. One maker's sheet calls it a rubber washer.
LocknutA wide nut that threads up the drain body. It clamps the whole drain to the bowl. One maker's instructions say to tighten it until the gasket above it is firmly seated against the sink.
Drain bodyThe threaded tube that carries the flange above the bowl. Below the bowl it carries the gasket and locknut. Portholes in its side must line up with the overflow channel, and an opening lower down takes the pivot rod.
Pivot rodA level rod that enters the side of the drain body. It passes through a nut with a ball inside it. It works like a seesaw: when the lift rod raises its outer end, the inner end pulls the stopper down to seal.
How this list was compiled: Part names and every detail line were checked, for facts only and with nothing copied, against pages read on 2026-09-19. Wikipedia: https://en.wikipedia.org/wiki/Sink (basin or bowl, faucet, drain, overflow, materials, stainless steel most common in kitchens); https://en.wikipedia.org/wiki/Plumbing_fixture (tailpiece as the first pipe from the drain to the trap, stop or service valve on each supply, supply tube, flood rim, overflow); https://en.wikipedia.org/wiki/Trap_(plumbing) (P-trap named for its shape, retained water as the seal, sewer gas, S-traps no longer accepted); https://en.wikipedia.org/wiki/Tap_(valve) (faucet in the US and tap in Britain, hot on the left in the United States, mixer and single-handle faucets, aerators); https://en.wikipedia.org/wiki/Faucet_aerator (what an aerator does, its housing, insert and rubber washer); https://en.wikipedia.org/wiki/Plug_(sanitation) (pop-up plug worked from a handle on the sink); https://en.wikipedia.org/wiki/Escutcheon_(furniture) (escutcheon where a pipe passes through a wall); https://en.wikipedia.org/wiki/Drain-waste-vent_system (every fixture has a trap and a vent). A drain-parts maker's articles: https://www.oatey.com/faqs-blog-videos-case-studies/blog/what-p-trap-and-how-does-it-work (J-bend, wall tube, slip joint washer and nut, the weir, a water seal of 1-1/2 to 2 inches); https://www.oatey.com/faqs-blog-videos-case-studies/blog/how-select-right-tubular-pipe-your-plumbing-projects (1-1/4 inch tubular parts for bathroom sinks and 1-1/2 inch for kitchen sinks, wall tubes also sold as wall bends, branch tailpieces); https://www.oatey.com/faqs-blog-videos-case-studies/blog/oatey-101-stops-and-supply-lines (stop valves, angle and straight stops, braided stainless steel or vinyl supply lines, rigid risers); https://www.oatey.com/faqs-blog-videos-case-studies/blog/how-properly-use-plumbers-putty-tips-mistakes-avoid-and-when-use (putty under the flange, oil-based putty stains granite and marble); https://www.oatey.com/faqs-blog-videos-case-studies/blog/how-choose-right-sink-strainer (tailpiece, basket strainers). A tubular-drain maker: https://www.keeneymfg.com/plumbing_faqs (glossary entries for trap, lavatory, slip joint, branch tailpiece, stop and pop-up drain; a worn J bend as the most common cause of a leak under a sink; plastic tubular hand tightened only); https://www.keeneymfg.com/installation_instructions/1056-en-PP820-77 (pop-up body, locknut, rubber gasket, rod, strap and stopper of a sink pop-up assembly); https://www.keeneymfg.com/installation_instructions/131-en-PP19PC (portholes in the drain lined up with the sink overflow, locknut and rubber washer). A fixture maker's glossary: https://www.americanstandard-us.com/learn/glossary (faucet trim as handles and spout, top mount faucets, trap). Two plumbing companies' how-to pages: https://www.mrrooter.com/about/blog/how-to-install-a-sink-pop-up-drain-stopper/ (lift rod, pivot rod, horizontal rod, drain flange, drain body, lock nut, rubber gasket, the nut with the ball inside) and https://www.benjaminfranklinplumbing.com/expert-tips/general-plumbing/how-to-adjust-the-sink-stopper-in-your-drain-plu/ (the rod pulls the stopper down to seal). A home inspectors' association glossary: https://www.nachi.org/plumbing-terms.htm (flood level rim, P trap, a trap seal that is usually 2 inches deep, air gap). A government page: https://www.epa.gov/watersense/bathroom-faucets, last updated June 16, 2026 (WaterSense labeled bathroom sink faucets use at most 1.5 gallons per minute against a standard flow of 2.2). Licence: own work
The drawing: Drawn for this site, 2026-09-20. Our own original line drawing, built from our own geometry; nothing was traced or copied. Read for accuracy: the text of Wikipedia's articles "Trap (plumbing)" and "Sink", Oatey's guide "Oatey 101: Stops and Supply Lines" (an angle stop on a stub from the wall, outlet at 90 degrees), and this dataset's own researched part notes. Licence: own work
How it works
The parts of a sink come in two sets: what you see from above, and the pipes in the cabinet below. These are the parts of a bathroom sink with a pop-up drain, cut front to back, the drain enlarged.
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Follow the water from the wall and back
Water arrives at the shutoff valve on the wall, climbs the supply line and leaves through the aerator at the tip of the spout. It lands in the basin, passes the drain flange and drops down the tailpiece into the J-bend, where the water seal blocks sewer gas. The wall tube then carries it through the escutcheon and into the wall.
The parts of a sink drain, from the flange down
The close-up shows the parts of a drain inside the hole in the bowl. The drain flange is the ring you see from above. Under the bowl, a rubber gasket and a locknut clamp the drain body in place, and the pivot rod enters from the side to move the pop-up stopper.
For a first round pick Start here: 7 main parts. After it, the main button reviews the parts you missed.
Pick the group Drain close-up for the parts of a faucet drain. The drawing zooms in; Name it offers 4 choices, and Type it takes a typed name.
Print blank, write the 22 names from memory, then check them against Print labelled.
Questions and answers
What is the curved pipe under a sink called?
It is the J-bend, the lower half of the P-trap. One maker of tubular drain parts names a worn J-bend as the most common cause of a leak under a sink.
What is the small hole near the top of a bathroom sink for?
That is the overflow. It opens into a hidden channel inside the wall of the bowl, which leads down to the drain body. If the drain is closed and the faucet left running, water has a way out before it spills over the rim.
How does the rod behind the faucet close the drain?
Pulling the lift rod up raises the outer end of the pivot rod. The pivot rod rocks like a seesaw on a ball held in a nut on the drain body, so its inner end pulls the pop-up stopper down to seal.