A bicycle, also called a pedal cycle, bike, push-bike or cycle, is a human-powered or motor-powered assisted, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A bicycle rider is called a cyclist, or bicyclist.

The frame is the very foundation of the bike as it is where the other components of the bike are installed such as the wheels, the handlebars, and the like.

The saddle is the seat attached to the seat post. The saddle is usually compatible with seat post regardless of sizing so this is not a problem as long as you choose a saddle you’re comfortable with.

The handlebars connect to the stem that connects to the fork that connects to the front wheel, and the whole assembly connects to the bike and rotates about the steering axis via the headset bearings.

The pedal is the part of a bicycle that the rider pushes with their foot to propel the vehicle. It provides the connection between the cyclist's foot or shoe and the crank allowing the leg to turn the bottom bracket spindle and propel the bicycle's wheels.

More Info: en.wikipedia.org