symbol

    A formal argument that is successively replaced with the
    specified characters enclosed in angle brackets (<>).  If no
    formal argument is specified, the assembler displays an error
    message.

 <STRING>

    A sequence of characters enclosed in angle brackets and used in
    the expansion of the indefinite repeat range. Although the angle
    brackets are required only when the string contains separating
    characters, their use is recommended for legibility.

 range

    The block of source text to be repeated once for each occurrence
    of a character in the list. The range can contain macro
    definitions and repeat ranges. .MEXIT is legal within the range.