A noun in The Etymologies of the 1930s glossed “dust” derived from the root ᴹ√ÁS-AT (Ety/ÁS-AT). It was also mentioned in The Feanorian Alphabet from the late 1930s with the same form and meaning (PE22/21-22), and in the revisions of that document from the 1940s, though there it was replaced with ᴹQ. osto as a name for one of the tengwar (PE22/50). This replacement may only have to do with tengwar names, and doesn’t necessarily invalidate asto “dust”.