Computing, as a subject, has very precise terminology which describes specific situations or systems. Within programming, the terminology must often be more precise.

Class

A class is a group of variables, or structure, used in such languages as C++, Java, SmallTalk, Delphi, and others. Classes are used primarily to group variables that are all properties of a common object. For example, to print a student's name and age, one can do it without classes like this:

void DescribeStudent ( int Student )
{
   printf( "Name: %s %s\nAge: %d\n", StudentFirstName[Student], StudentLastName[Student], StudentAge[Student] );
}

The code would look much better with classes, however:

void DescribeStudent ( student Student )
{
   printf( "Name: %s %s\nAge: %d\n", Student.FirstName, Student.LastName, Student.Age );
}

In that example "student" is the class and "Student" is an instance of the class. Classes can also have functions belonging to them, as in this example:

void student::Describe ( )
{
   printf( "Name: %s %s\nAge: %d\n", FirstName, LastName, Age );
}

"Describe" is a method of the class "student".

Compiler

A tool which builds executable files from source code files, ready for running or testing.

A commonly used compiler is the GCC package, which builds programs from C source code files.

OOP

OOP, or Object-Oriented Programming, refers to a programming practice in which most or all data is stored in groups called classes in order to make the code more organized and intuitive. You might have a Person class with a TalkTo method, doing something like:

Person Amy( "Amy", Person.Female );
Person Bob( "Bob", Person.Male );
Bob.TalkTo( Amy );

Amy and Bob are instances of the class Person, and let's assume each person has a name, gender, and mood. The TalkTo function sets the mood of the talker and talkee. Without OOP, the messy alternative would be something akin to:

int AmyMood = 0;
int BobMood = 0;
PERSON_TalkTo( "Bob", PERSON_MALE, &BobMood, "Amy", PERSON_FEMALE, &AmyMood );

It is much less intuitive. For this reason, most modern-day languages support some form of OOP. SmallTalk is a pure OO language, meaning everything, even basic types like integers, are objects. Java is OO but with primitives (like integers). C++ and Delphi support OOP, but don't require it.

IDE

An IDE, or Integrated Development Environment, is a program that presents an environment in which the programmer has easy access to various tools through a graphical user interface. Programming requires a text editor, compiler, often a debugger, and usually a linker. An IDE presents a common interface for all of them -- the programmer just clicks a button to compile, double-clicks a file to open it, etc.

IDEs are often built to work with a specific set of tools. Examples these are Dev-C++ for the GCC compiler, Microsoft Visual Studio, etc.

Resource

A resource is any data stored in an application that is not part of the code itself. Applications are not pure code; they have a section reserved for resources, and those resources can be accessed by the application itself or by any other application. Icons are probably the most common resource, though dialogs, menus, and version tables are also used frequently. When you right-click an application in Windows and click Properties, the information you are seeing is read from a version table stored as a resource in the application.