Plural of Bias

by Craig Shrives
The Quick Answer
The plural of bias is biases. The plural form with a double s (biasses) is obsolete.

The Plural of Bias

The plural of bias is biases. In other words, the noun bias forms its plural in a standard way. The es ending is not pronounced "eez" as with analyses and oases (from analysis and oasis). Also of note, biasses (an old form of the plural with a double s) is now obsolete.
  • At the end, ignorance is the source of biases. If we cure that, there's nothing to fear and hate. (Musician Daryl Davis)
  • I'm not staid and unbiased here. I have certain biases I want to convey, and if you disagree, that's fine. (Newsreader Neil Cavuto)
The noun bias 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
scythe
add s lamps
scythes
Noun Ending s, sh, ch, x or z box
dress
bias
add es boxes
dresses
biases
Nouns ending [consonant] o zero
tomato
add either s or es
(There are no rules for this - you have to know.)
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 donkey
chimney
add s donkeys
chimneys
Nouns ending f or fe dwarf
hoof
ves and/or s
(There are no rules - you have to know.)
dwarfs
hooves or hoofs
Nouns ending is oasis
diagnosis
change the is to es oases
diagnoses
Exceptions man
louse
some nouns undergo a vowel or letters change men
lice
More exceptions salmon
sheep
some nouns do not change at all salmon
sheep
Foreign rulings fungus
medium
some nouns adopt foreign rulings fungi
media
Read more about English spelling rules.

Why Is There Confusion over the Plural of Bias?

Bias looks a little a like analysis and oasis, both of which derive from Greek. The plurals of analysis and oasis are analyses and oases (pronounced with an "eez" ending), and this leads to some mistakenly giving biases a similar "eez" ending. Bias does not derive from Greek, and it does not end -is.

The old plural biasses is now obsolete. [evidence]

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See Also

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

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