A function-name is a word that is one of a specified list of words used in COBOL source programs.
A function-name specifies the mechanism provided by ILE COBOL to determine the value of an intrinsic function.
With the exception of the words LENGTH, RANDOM, SUM, and WHEN-COMPILED, a word that is a function-name, in a different context, can appear in a program as a user-defined word, a system-name, or a context-sensitive word.