Reserved words

A reserved word is a character-string with a predefined meaning in a COBOL source unit.

Reserved words are listed in Reserved words. There are five types of reserved words:

  • Keywords
  • Optional words
  • Figurative constants
  • Special character words
  • Special registers
Keywords
Keywords are reserved words that are required within a given clause, entry, or statement. Within each format, such words appear in uppercase on the main path.
Optional words
Optional words are reserved words that can be included in the format of a clause, entry, or statement in order to improve readability. They have no effect on the execution of the program.
Figurative constants
See Figurative constants.
Special character words
There are five types of special character words, which are recognized as special characters only when represented in single-byte characters:
Special registers
See Special registers.