A "component" is a single part of something larger. For instance, an engine is a component of a car and a piston is a component of an engine.
An object's "composition" is everything that makes up the object. So, we can say that the engine, pistons, aluminum, steel, and paint are "components" that make up the car's "composition."
One website that might help you with questions like this in the future is --
http://www.prefixsuffix.com/. I do not know if it will be of help to you since it is entirely in English, but it lets you search prefixes and suffixes of words and tells you what they mean. For instance, when I searched "com-" from your word "component," it said the "com-" means "with or together," which implies that a "component" works "together" with other components in a larger object.
I hope this might help you, and good luck with you studying.