This diagram and the detail photos below it, show what the parts of a modern road bicycle are called. Knowing the bike component names (nomenclature) and how to correctly identify them will help you when you need to explain something to a mechanic working on your bike, when you're shopping for upgrades and when you're talking about bikes to other cyclists. Another excellent resource is Sheldon Brown’s bicycle glossary.
Notes: Hidden by the crankset in this picture is the bottom bracket. There are actually two bottom brackets.
You call the bearing assembly that the crankset spins on, the bottom bracket (marked A in the photo; the mechanic is holding the end of the bottom bracket axle that runs through the frame and that the crankarms attach to). Mechanics and cyclists often say “BB” instead of bottom bracket.
And you also call the part of the frame that the bottom bracket bearing assembly is screwed or pressed into, the bottom bracket (marked B). Cyclists and mechanics can call it the bottom bracket "shell," too.
Finding a bicycle's
The headset is like the bottom bracket, and instead of holding the bearings for pedaling the bicycle as the BB does, it holds the bearings for steering. It is also the mechanism that joins the fork to the frame.
While headsets seem mysterious because, like the BB, everything is hidden inside, quality headsets are comprised of relatively few parts. They are usually reliable and mostly trouble-free. If repairs are needed, it's often a quick adjustment.
Pedals with toe
clips and straps
Toe clips prevent your feet slipping off the pedals when you're pedaling, something that can lead to the pedal striking and cutting your shin, a potentially serious, and painful injury. Toe clips and straps also hold your feet in the right position for efficient pedaling. Plus, they can be tightened to lock your feet on the pedals for even more pedal power.
The clipless and cleat connecting mechanism is based on ski bindings that lock your boots to the skis. Clipless pedals provide even more efficient pedaling than toe clips and straps, which is why enthusiasts and racers prefer them. They are also easier to enter and exit.
For road riding, I use and recommend, Look Keo and Speedplay Zero clipless pedals. On my mountain bikes I use and recommend Shimano SPDs. For commuting and touring, a great choice is Shimano's dual-sided A324 pedals (clipless on one side, platform on the other)..
Two notes on confusing marketing jargon and misnomers/mistakes (please feel free to submit more and I may add them to this list).
1. Regarding clipless pedals, you may hear riders say "clip into your pedals." That's a misnomer. You can't clip into clipless pedals because there are no clips. What you want to say is "click into your pedals," because when you enter clipless pedals the cleats click into place.
2. Recently the sailing, aircraft and automobile term "cockpit" has become slang for a bicycle handlebars and controls (wikpedia says cockpit was first used in the 1580s and meant a pit for fighting cocks). Now you read it in catalogs and bicycle reviews sometimes used to describe the bars, controls and seat. It may seem clever—one of those things that you kind of know what it means—but it's not an accurate bicycle term and requires guessing exactly which parts are being referred to. To be sure which components are being described, you usually need to search the bicycle specifications chart.