beachgrass /ˈbit͡ʃˌɡɹæs/ noun3 •Any grass of the genus Ammophila. •Ammophila arenaria, a coarse grass native to sandy beaches of Europe (north to Iceland) and northwest Africa. •Ammophila breviligulata, a coarse grass native to sandy beaches of eastern North America, including the shores of the Great Lakes. formsbeachgrasses