The head tube is the part of the frame that holds the fork/headset.

The housing stop holds the wires between the levers and the gears/brakes. These are placed on bottom of the top tube.

The brake hoods are placed on your handlebar. They are the reason why the top of your handlebar, at the levers, are called "hoods". They are made in rubber and hides the wires from the levers going to the gears and brakes.

The cable housing keeps your cables hidden and protects it. It also makes the bike look better since they can be made in any colours.

The levers are the two metal/placstic pieces on the handlebar that you use to brake and change gears with. One of the levers controls one of the gears and brake, while the other lever uses the other brake and gears. If you push the levers back you brake, and if you push them to the side you will shift your gear.

The handlebar is what you hold your hands on when riding your bike. It is connected with the stem and holds the levers.

The fork is what holds the front wheel to the bike. It is connected on the frame via the head tube.

The fork crown connects the two ends holding the wheel, and the steering tube that is connected with the frame via the head tube.

The hub is what is placed in the center of the wheels. The hub contains bearings and got a hole in them, so a quick release can go through them. They are connected with the bike via the quick releases.

The quick releases are what connects the wheels with the bike. They are a long thin stick that goes through the hubs of the wheels.

The front dropout is what holds the quick releases on the frame of the bike. They are made so they grap around the quick releases and therefore make sure you won't crash because of the front wheel falling out.

The valve stem is what you use to get air in the tubes of your tires. The valve makes sure that the air doesnt get out of the tubes as easy as it can get in.