Library /sys$common/syshlp/lse$clihelp.hlb DEFINE, KEY, Parameter  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 key-specifier
    Specifies a keyword that indicates the key to be defined. If you
    use the DEFINE KEY command to change the definition of a key that
    was previously defined, LSE does not save the previous definition.

 string
    Specifies an LSE command to be executed when the key is pressed.
    This is a required parameter unless you use the /LEARN qualifier;
    you cannot use the string parameter with either the /LEARN
    qualifier or the /STATE=GOLD qualifier.