Grass, in horticulture, the surface layer of soil with its dense and matted vegetation, usually grasses cultivated for ornamental or recreational use. Grass grasses are classified according to climate. The turf is the top layer of a grassy area consisting of a kind of carpet of grass and its roots. It's the layer that you can cut and lift in one piece.
Lawn is a gardening and gardening term for grass used on a lawn. This type of grass contrasts with ornamental grasses, which are generally larger, taller and grow in clusters. The best-known types of grass include St. Augustine grass, centipede and zoisia grass.
By definition, a lawn is a residential, commercial, or industrial land on which grass grows. Grass is the term used by horticulturists to refer to grass that is cut and maintained with the same uses as a lawn.