6.1.0550
>BODY
to-body
CORE
 
( xt -- a-addr )

a-addr is the data-field address corresponding to xt. An ambiguous condition exists if xt is not for a word defined via CREATE.

See:
3.3.3 Data space, A.6.1.0550 >BODY.

Rationale:
a-addr is the address that HERE would have returned had it been executed immediately after the execution of the CREATE that defined xt.
Testing:
T{  CREATE CR0 ->      }T
T{ ' CR0 >BODY -> HERE }T