1. sand , so called from its loose, crumbling nature (from ψάω); (Odyssey by Homer), etc.:—;proverbial, ψάμμος ἀριθμὸν περιπέφευγεν (Pindar)

2. ἡ ψ. the sandy desert of Libya, (Herdotus Historicus)

Both ψάμμος and ψάμαθος sometimes drop ψ and become ἄμμος, ἄμαθος. (ML)