Associates an equivalence string and a set of attributes with a key on
 the terminal keyboard.

    DEFINE/KEY  KEY-NAME  EQUIVALENCE-STRING

       Qualifiers             Defaults

       /[NO]ECHO              /ECHO
       /[NO]ERASE             /NOERASE
       /IF_STATE=(state-name) /NOIF_STATE
       /[NO]LOCK_STATE        /NOLOCK_STATE
       /[NO]LOG               /LOG
       /SET_STATE=(state-name)/NOSET_STATE
       /[NO]TERMINATE         /NOTERMINATE