When I want to declare a variable I must give it a type and an identifier.

/* Integer Sheep Counter */
int count ;

The word count is an identifier. It gives a name to something which we will use to identify it. The word main is also an identifier, in that it identifies a particular function. C has rules about what constitutes a valid identifier:

1. An identifier must not be a keyword
2. An identifier must start with a letter, and then contain nothing but letters, digits and the underscore "_" character.

Thus count is a valid identifier, as is count99. Of course 2be is not a valid identifier, it is part of a quote from Shakespeare. You invent your own identifiers when you write your programs. I want to do some simple counting, so I have created a variable with the name count.

Remember that the identifier is not present in the program which the compiler actually creates, it is simply used by you to refer to a particular thing. This means that the variable names can be as long and meaningful as you like, without any waste of program space.

Whole books have been written about sensible names for variables (but they are very boring). Use names which make sense to you and back them up with comments where appropriate, for example:

/* number of sheep in our field */
int sheep ;

/*  Simple Variable  */
void main ( void )
{
  /* create an integer variable  */
  int count ;
}