Plural noun exceptions photo – photos piano – pianos halo – halos gas – gases (gasses is also acceptable but less common)
With the unique word volcano, you can apply the standard pluralization for words that end in –o or not. It’s your choice! Both of the following are correct:
volcanoes volcanos If the singular noun ends in –us, the plural ending is frequently –i.
cactus – cacti focus – foci If the singular noun ends in –is, the plural ending is frequently –es.
analysis – analyses ellipsis – ellipses If the singular noun ends in –on, the plural ending is –a.
phenomenon – phenomena criterion – criteria Some nouns don’t change at all when they’re pluralized.
sheep – sheep series – series species – species deer – deer You need to see these nouns in context to identify them as singular or plural. Consider the following sentence:
Mark caught one fish, but I caught three fish.
However, when it comes to fish, things can get a little complicated.
Plural noun rules for irregular nouns Irregular nouns follow no specific rules, so it’s best to memorize these or look up the proper pluralization in the dictionary.
child – children goose – geese man – men woman – women tooth – teeth foot – feet mouse – mice person – people
