VMS Help FORTRAN, Data, Expressions, Character  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  Character expressions consist of character elements and character
  operators.  Evaluation of a character expression yields a single
  value of character data type.  A character element can be a
  constant, variable, record element, array element, substring,
  expression (optionally enclosed in parentheses), or a function
  reference.

  A character expression has the form:

    character element[//character element]...

  The concatenation operator (//) is the only character operator.
  Concatenation is from left to right.