SC -corn in the USA

[Decker, Terry D.]

One of the most common thickeners is corn starch, which is a superfine,
clinging, slick, white, powdered starch extracted from maize.  It is not a
flour.  Arrowroot powder which is either the ground tuber or the starch
extracted from the tuber of the arrowroot is also used as a thickener, but I
have no experience with it.

All purpose flour is a mixture of hard and soft flours in general us in US
homes and is also a common thickener.  Rice flour is less common, but
available.

The one product which comes closest to what you describe is a blend of wheat
and rice flours resembling a very fine granulated sugar marketed under the
brand name Wondra.  

Bear

 
> So, what would you call the ultra-fine (and we are talking as 
> fine icing
> sugar) flour in the States?  It is used for thickening and so 
> on just like
> the maize product you call "corn starch" (which term I have 
> met before in
> American cookbooks).
> 
> Gwynydd