There are two type of functions in the coldfusion markup language - custom tags and user defined functions. In CFML, the grouping of the similar functions and user defined tags can be done because sometimes functions are used at various places in an application as per  according to their use and purpose. It is helpful in keeping the memory saved and library management easy.
To create a component in the coldfusion programming, there are following tags used for the coldfusion like -
cfcomponent - to define the component structure
cffunction - creates functions within the cfcomponent
cfargument - creates arguments and parameters to the predefined function
cfproperty - to define the properties and methods within the component
Class -
In any object oriented programming language, the class has the different scope of work. A class is considered as an entity which is always represented by its object. A class is generally considered the home of the different methods & variables and it has also a separate role in CFML.
Methods -
A method is generally considered as the other component of the CFML language. Generally a separate method does not do anything. To make it workable, separate functions are needed to call in a method.       
Object -
An object is considered as the instance of a class. In CFML, it is created by using the cffunction tag and createobject() is used to declare the object of a class.