As nouns the difference between grass and fern
is that
grass is any plant of the family Poaceae, characterized by leaves that arise from nodes in the stem and leaf bases that wrap around the stem, especially those grown as ground cover rather than for grain while
fern is any of a group of some twenty thousand species of vascular plants classified in the division Pteridophyta that lack seeds and reproduce by shedding spores to initiate an alternation of generations.
As proper nouns the difference between grass and fern
is that
grass is {{surname|lang=en} while
Fern is {{given name|female}} from the fern plant.
As a verb grass
is to lay out on the grass; to knock down (an opponent etc.).