"Masses" is one version, as in "When worlds collide, masses often merge."
There is no plural. The word 'public' is a mass noun.
The word 'mucous' is an adjective, it has no plural form.The noun 'mucus' is an uncountable (mass) noun as a word for a substance.
Men at arms. The word 'arms' is a mass noun - and is already plural.
No, the noun 'rain' is a singular, uncountable (mass) noun as a word for water drops falling from clouds; a word for percipitation.The plural noun 'rains' is a plural uncountable (mass) noun as a word specifically for seasons or periods of rain.
There is no plural form for mankind. The noun mankind is an uncountable (mass) noun, a word for all humans considered as a single group, a word for a concept.
The noun 'refuse' is a mass (uncountable) noun with no plural form. The noun 'refuse' is a word for a something discarded, trash, rubbish, garbage; a word for a substance.
The word stars is a count noun, the plural form for the singular star. A count noun is a word that has both a singular and a plural form.
The noun 'food' is a mass (uncountable) noun as a word for a substance.The plural noun foods is a word for 'types of' or 'kinds of' food.
The noun 'rain' is a singular, uncountable (mass) noun as a word for water drops falling from clouds; a word for precipitation.The plural noun 'rains' is a plural, uncountable (mass) noun as a word specifically for seasons or periods of rain.
The singular noun is mass. The plural form is masses.
Nouns that have no plural form are called mass nouns, uncountable nouns, or non-count nouns.
The noun 'punctuation' is a mass noun (also called an uncountable noun), it has no plural form.The noun 'punctuation' is a type of aggregate noun, a word representing an indefinite number of elements.