Plural Nouns for Words Ending in o

How to make nouns plural when they end in “o”?
Pluralization of words ending in “-o” is tricky because there’s no single, completely reliable rule, but there are some helpful patterns.

General Tendencies:

• Words ending in -o preceded by a vowel usually just take -s: This is a pretty consistent rule.
• Most words ending in -o preceded by a consonant take -es: This is the most common pattern.
• Many words of foreign origin (especially musical terms) take -s: This is another helpful guideline.
• Abbreviations: Almost always just -s.

Here’s a breakdown with examples:

1. Words ending in vowel + -o (almost always take -s):
   bamboo → bamboos
   cuckoo → cuckoos
   folio → folios
   kangaroo → kangaroos
   portfolio → portfolios
   radio → radios
   scenario → scenarios
   stereo → stereos
   tattoo → tattoos
   video → videos
   zoo → zoos
   

2. Words ending in consonant + -o (mostly take -es):
   Common examples taking -es:
   echo → echoes
   hero → heroes
   potato → potatoes
   tomato → tomatoes
   torpedo → torpedoes
   veto → vetoes
   volcano → volcanoes
   

Common exceptions (taking only -s):
auto → autos
casino → casinos
dynamo → dynamos
kilo → kilos
photo → photos

3. Musical terms (usually take -s):
   Many musical terms borrowed from Italian follow this pattern:
   cello → cellos
   concerto → concertos
   libretto → librettos
   piano → pianos
   solo → solos
   soprano → sopranos
   

4. Abbreviations (almost always take -s):
   memo → memos
   pro → pros
   

The following diagram shows some examples of the rules to make nouns plural when they end in “o”. Scroll down the page for more examples.

 

Tips for Remembering:

• Vowel + -o: Almost always just -s.
• Consonant + -o: Usually -es, but many exceptions exist.
• Foreign origin/musical terms: Often just -s.
• Abbreviations: Almost always just -s.

Rules for forming plural of nouns
The most common way to form the plural of a noun is by adding “-s” to the end.
cat → cats
dog → dogs
book → books
Make plural nouns by adding s

Words ending in -s, -ss, -sh, -ch, -x, or -z: Add “-es” to form the plural.
This is because adding just “-s” would make the word difficult to pronounce.
bus → buses
dress → dresses
Make plural nouns by adding es

Words ending in consonant + -y: Change the “y” to “-ies”.
baby → babies
story → stories
Words ending in vowel + -y: Simply add “-s”.
boy → boys
day → days
Plural nouns for words ending in y

Words ending in -f or -fe: In many cases, change the “f” or “fe” to “-ves”. However, some words just add “-s”.
leaf → leaves
chief → chiefs
Plural nouns for words ending in f or fe

Words ending in -o: Generally add “-es,” but some words just add “-s.” There’s no perfect rule, so memorization is often necessary.
potato → potatoes
photo → photos
Plural nouns for words ending in o

Irregular Plurals:
Some nouns have irregular plural forms that don’t follow any of the above rules. These must be memorized.
man → men
child → children
foot → feet
ox → oxen
Nouns with the Same Singular and Plural Form:
Some nouns have the same form in both singular and plural.
sheep
deer
Irregular plural nouns

Spelling Rules: Making Plurals by Adding ‘ies’
If the word ends consonant ‘y’ don’t stress
Change ‘y’ to an ‘i’ and then add ’es’

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ies - Plurals - fairies, ladies

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Plural Nouns in English | Regular & Irregular Plural Nouns | Plurals Spelling
Regular nouns adding -s to the end.
Nouns ending in s, ch, sh, x, and z (adding -es to the end)
Nouns ending in f or fe (the -ves rule)
Nouns ending in a vowel + y (add -s to the end)
Nouns ending in a consonant + y (the -ies rule)
Nouns ending in a vowel + o (add -s to the end)
Nouns ending in a consonant + o (the -es rule)
Irregular nouns that do not end in s in their plural form (e.g. child)
Nouns that remain the same in singular and plural form (e.g. sheep)

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Plural Nouns
Plural Nouns, add -s	Plural Nouns, add -es	Words ending with y
Words ending with f or fe	Words ending with o	Irregular Plural Nouns
Summary of Plural Nouns

Other Digraphs
AR Sound	Er,Ir,Ur	OR Sound
Ar,Er,Ir,Or,Ur	Ou, Ow	Oi, Oy
OO Sound

Free Printable Worksheets for Consonant Digraphs

These worksheets focus on the consonant digraphs: ch, sh, th, qu and ng.

Printable Worksheets (Consonant Digraphs)
Learning "ch"	Learning "sh"
Learning "th"	Learning "qu"
Learning "ng"

Free Printable Worksheets for Digraphs

Printable Worksheets (EE, OO, OU, OI, AW)
EE Words	OO Words
OI Words	AW Words

Learn the sound of the letters

Learning Short Vowels

Short Vowels
Short A	Short E	Short I
Short O	Short U	Short Vowels

Learning Long Vowels

Long Vowels
Long A	Long E	Long I
Long O	Long U	Y (vowel)
Long Vowels	Short & Long Vowels

Compare Short & Long Vowels

Short & Long Vowels
Short & Long A	Short & Long E	Short & Long I
Short & Long O	Short & Long U

Learning Consonants

Consonants
Letter B	Hard C	Soft C
Letter D	Letter F	Hard G
Soft G	Letter H	Letter J
Letter K	Letter L	Letter M
Letter N	Letter P	Letter Q
Letter R	Letter S	Letter T
Letter V	Letter W	Letter X
Letter Y	Letter Z

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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