Plural of Domino

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The Quick Answer
The plural of domino is dominoes or dominos.

The Plural of Domino

The plural of domino is dominoes or dominos.
  • European-style dominoes are traditionally made of ivory.
  • The game of dominos is played at a professional level, similar to poker.
The noun domino adheres to the standard rules for forming the plurals of nouns in English (shown in the table below).

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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 lamp
add s lamps
Noun Ending s, sh, ch, x or z bus
add es buses
Nouns ending [consonant] o domino
add either s or es
(There are no rules for this - you have to know.)
dominoes or dominos
Nouns ending [vowel] o patio
add s patios
Nouns ending [consonant] y story
change the y to an i and add es stories
Nouns ending [vowel] y storey ()
add s storeys
Nouns ending f or fe dwarf
ves and/or s
(There are no rules - you have to know.)
Exceptions man
some nouns undergo a vowel or letters change men
More exceptions salmon
some nouns do not change at all salmon

Why Is There Confusion over the Plural of Domino?

There is confusion because the rule for forming plurals with nouns ending in o isn't straightforward. Most nouns will just add an s. For example:
  • Kangaroo becomes kangaroos.
  • Piano becomes pianos.
Some add es. For example:
  • Tomato becomes tomatoes.
  • Potato becomes potatoes.
With some words, both versions are accepted. For example:
  • Flamingo becomes flamingoes or flamingos.
  • Echo becomes echoes or echos.
The plural of domino can be either dominoes or dominos.. Unfortunately, there is no clever way of knowing which nouns ending o follow which rules. You have to know. (For example, you have to know that piano becomes pianos, but tomatos becomes tomatoes.)

Though dominos and dominoes are both accepted plurals, dominoes is the more common of the two. (See the difference in Google's Ngram Viewer.)
Another Interactive Exercise
Here are three randomly selected questions from another exercise on plurals, which can be edited, printed to create an exercise worksheet, or sent via email to friends or students.

See Also

Unusual pluralsPlural forming table Quirks with forming plurals Forming the plurals of abbreviations Forming the plurals of compound nouns