* CAT` ( "ccc" -- )

This word has only compile-time semantics, just like
CAT". It appends run-time semantics to the current
definition that concatenates the back-ticked string according
to the specification for CAT. An error is thrown if the
length of the quoted string is longer than the system
parameter MAX_DATA_STR (see S,).

FORTH/DEF dstrings compiling primitive