Variable: Variables are containers for storing data values. They are reserved memory locations that stores values.
Identifier: Identifier is a name used to identify a variable, function, class, module or other object. An identifier starts with a letter A to Z or a to z or an underscore (_) followed by zero or more letters, underscores and digits (0 to 9).
The rule of an identifier:
The first character of an identifier must be an underscore(‘_’) or a letter (upper or lowercase).
The rest of the identifier name can be underscore(‘_’), letter(upper or lower case) or digits(0-9).
Identifier name are case-sensitive.
Punctuation characters such as @, $, % are not allowed within identifier.