The word "four-leaf" or "four leaf" is not a noun, it is an adjective used to describe a noun, for example a four-leaf table or a four-leaf configuration.The noun form of the adjective "four leaf" is four-leaf clover, a word for a type of plant.
The possessive form for the noun leaf is leaf's.Example: A leaf's imprint was left on the window.
The noun grass is a mass noun. The noun grass is described in terms of some grass, covered in grass, a patch of grass, a field of grass, a blade of grass or blades of grass. The plural form, grasses, is reserved for 'types of' or 'kinds of', for example: A variety of grasses covered the great plains. Some grasses native to the great plains are slough grass, Canada wild rye, inland saltgrass, desert saltgrass, needle and thread grass, and porcupine grass.
There is no abstract noun form of the concrete noun leaf, a word for a physical object.
The word leaf is primarily a noun, but it can also be used as a verb, as in "to leaf through a book."
The word leaf is a noun. Leaf can also be a verb as in to leaf through a book.
mass
The plural form for the noun leaf is leaves.
The noun 'hydrogen' is a mass noun (an uncountable noun) as a word for a substance.
no
Their masses are similar the only difference in their value making the leaf have less mass.
Mass can be a noun or an adjective. As a noun: The mass of a solid. As an adj: Mass production.