Cupful is singular; cupfuls is the plural.
The word cupful is a singular, common noun, a word for a thing.
Cupfuls
cupfulls
cupfuls
The plural form of cupful is cupfuls.
No, the noun cupful is a concrete noun; a word for an amount of a substance; a word for a physical measurement.
cupsful grandchildren People disagree if the plural is cupsful or cupfuls. Some compound words have the plural endings on the first noun element instead of the whole compound. The first noun is the prinicpal word. In cupsful -ful is not a word it is a suffix. Other examples sisters in law commanders in chief
Cupful's
The plural of the noun "half" is "halves."
The plural noun for path is paths. The plural noun for patch is patches.
The plural noun of general is generals. Generals is a regular plural noun.