Plural of Tooth

The Plural of Tooth

The plural of "tooth" is "teeth."

• Sharks grow a new set of teeth every two weeks to replace worn teeth.
• I told my dentist my teeth are going yellow. he told me to wear a brown tie. (Rodney Dangerfield)

Some words do not form their plurals by adding 's' to the end but by changing their forms (e.g., man becomes men, foot becomes feet, mouse becomes mice).

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The Standard Rules for Forming the Plurals

The table below shows the standard rules for forming the plurals of nouns in English.

Type	Example of Type	Forming the Plural	Plural
Most Nouns	cat scythe	add s	cats scythes
Noun Ending s, sh, ch, x or z	bus dress	add es	buses dresses
Nouns ending [consonant] o	mango zero tomato	add either s or es (There are no rules for this - you have to know.)	mangoes or mangos zeros tomatoes
Nouns ending [vowel] o	patio ratio	add s	patios ratios
Nouns ending [consonant] y	story penny	change the y to an i and add es	stories pennies
Nouns ending [vowel] y	storey () donkey	add s	storeys donkeys
Nouns ending f or fe	dwarf knife	ves and/or s (There are no rules - you have to know.)	dwarfs knives
Exceptions	tooth louse	some nouns undergo a vowel or letters change	teeth lice
More exceptions	salmon sheep	some nouns do not change at all	salmon sheep

Read more about English spelling rules.

Why Is There Confusion over the Plural of Tooth?

There is confusion because the plural of "tooth" is not formed by adding 's' but by changing its central vowel. Several other words form their plurals in this way. There is no rule to remember them. They have to be memorized.