| Noun | 1. | grass wrack - submerged marine plant with very long narrow leaves found in abundance along North Atlantic coastsgenus Zostera, Zostera - (or in some classifications family Zosteraceae) small genus of widely distributed marine plants aquatic plant, hydrophyte, hydrophytic plant, water plant - a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth |