Because of their elusive, abstract nature.
Abstract terms can be difficult to define because they often represent complex ideas or concepts that do not have a clear, concrete representation. Since abstract terms can vary in meaning depending on context or individual interpretation, defining them in a precise and universally accepted manner can be challenging. Additionally, abstract concepts may be subjective and open to different perspectives, making them more elusive to pin down in a concise definition.
Perhaps one reason energy is hard to define is that we only seem to be able to define it in terms of what it DOES rather than what it IS.
define 'Want' in marketing terms
Yes, a class can be defined as final and abstract also.
The abstract noun for the adjective hard is hardness.
The term interface class does not exist in C#. If this is a term describing a class being an interface to other component (human, subsystems, etc), it is very application specific. The designer of that application should know the abstraction.However, C# does have another type called interface. An interface is NOT a class. An interface defines the intention of some behaviors that classes may be extended it and provides the implementation. The intention, is nothing but method signatures, which defines the return data type, the method name, and any method arguments and associated data type. The implementation is the code of the method. Interface is used for separating the concern of design and implementation.Abstract class is a class with abstract keyword. It can be just like a class without that keyword (then, why it is an abstract class?). But it may have some methods or properties defined as abstract. These abstract methods, like the method signatures of an interface, defines the intention.The subclasses of such an abstract class would need to implement those abstract methods (providing the code).There are more common, differences between interfaces and abstract classes, please see answer(s) of those related questions in C# category.
"Defined items" are defined in terms of "undefined terms".
It is hard to define matter because it changes. It is the composed to atom.
The noun forms for the verb to define are difinability, definement, and the gerund, defining. Another noun form is definition.
The noun forms for the verb to define are difinability, definement, and the gerund, defining. Another noun form is definition.
are you asking for help on finding definition for geometric terms? if so go to: http://library.thinkquest.org/2647/geometry/glossary.htm#b and to wikipedia for x and j terms
the three terms; point, line and plane can be defined although it is called the undefined terms still we know and we can define the meanings of that terms.. common sense? joke.
define output and input ecosystem/