MapAll
MapAll[f, expr] or f //@ expr applies f to every subexpression in expr.
Example: MapAll[f, a,b,c,d]. MapAll[f, expr] is equivalent to Map[f, expr, 0, Infinity]. See The Mathematica Book on the web: Section 2.2.4. See also: ExpandAll, ReplaceAll.
Further Examples
MapAll[f, expr] or f //@ expr applies f to every subexpression in expr. 
a,b
,
c,d
]
. 
0, Infinity
]. 