zos-grass|ˈzɒsgrɑːs, -æ-| [Abbrev. of zostera + grass n.1] = zostera. 1937J. W. Day Sporting Adventure 129 Five ducks come out of the sunset and swing low above me out to the muds and bared zos grass.1974Times 9 Mar. 14/1 They [sc. brent geese] cleared the mud-flats of the zos-grass, their natural feed.