diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -2432,10 +2432,10 @@
 }
 
 PyDoc_STRVAR(sum_doc,
-"sum(sequence[, start]) -> value\n\
+"sum(iterable[, start]) -> value\n\
 \n\
-Return the sum of a sequence of numbers (NOT strings) plus the value\n\
-of parameter 'start' (which defaults to 0).  When the sequence is\n\
+Return the sum of an iterable or sequence of numbers (NOT strings) \n\
+plus the value of 'start' (which defaults to 0).  When the sequence is\n\
 empty, return start.");