typo

README.md

@@ -1064,7 +1064,7 @@ Thus, by default the stack generator assumes that the input data is an array of
 
 <a name="stack_order" href="#stack_order">#</a> <i>stack</i>.<b>order</b>([<i>order</i>]) · [Source](https://github.com/d3/d3-shape/blob/master/src/stack.js)
 
-If *order* is specified, sets the order accessor to the specified function or array and returns this stack generator. If *order* is not specified, returns the current order acccesor, which defaults to [stackOrderNone](#stackOrderNone); this uses the order given by the [key accessor](#stack_key). See [stack orders](#stack-orders) for the built-in orders.
+If *order* is specified, sets the order accessor to the specified function or array and returns this stack generator. If *order* is not specified, returns the current order accessor, which defaults to [stackOrderNone](#stackOrderNone); this uses the order given by the [key accessor](#stack_key). See [stack orders](#stack-orders) for the built-in orders.
 
 If *order* is a function, it is passed the generated series array and must return an array of numeric indexes representing the stack order. For example, the default order is defined as: