What class is grass in?

Grasses belong to the kingdom plantae, to the phylum anthophyta, and to the class liliopsida. The liliopsida are what we generally call the monocots. Monocots are plants that produce a single leaf (as opposed to two leaves) with parallel veins (as opposed to branching veins). Monocots do not form wood. All of the grains in the world are monocots.