Yes.
In the sense that it looks like grass, is plant, has roots, has long elongated leafs with little to no stems growing out of the ground and can cover large area while being so close to each other to...
With the exception Bermuda grass, it will root if given enough moisture in the dirt.
Grass seed is the reproductive method of most grasses, so grass produces seeds which when sown produce new plants.
The grass means the grass the person is reffering to grass could be any grass in the world.
Learn About Ornamental Grasses
How to Divide Ornamental Grass Plants
The Unique Ornamental Grasses
How to Plant Grass Seeds