any of several large deciduous trees with rounded spreading crowns and smooth grey bark and small sweet edible triangular nuts enclosed in burs; north temperate regions
tall annual cereal grass bearing kernels on large ears: widely cultivated in America in many varieties; the principal cereal in Mexico and Central and South America since pre-Columbian times
hardy annual cereal grass widely cultivated in northern Europe where its grain is the chief ingredient of black bread and in North America for forage and soil improvement
valuable meadow and pasture grass in Europe and especially central United States having tall stalks and slender bright green leaves; a chief constituent in lawn grass mixtures
tall perennial grass that spreads by creeping rhizomes and is grown for fodder; naturalized in southern United States where it is a serious pest on cultivated land