Plural of Bias

What Is the Plural of Bias?

The Quick Answer

The plural of "bias" is "biases." The plural form with a double s ("biasses") is obsolete.

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

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]