"Criterion" is the singular (one criterion); "criteria" is the plural (two or more criteria). They must not be swapped.
Singular noun: one standard, principle, or test used to judge or decide something. Just as "phenomenon" is one phenomenon, "criterion" is one criterion — singular and countable.
The only criterion for joining the club is that you must be over eighteen.
Price was the most important criterion in her decision to switch providers.
What is the main criterion used to evaluate performance in this department?
Plural noun: two or more criteria. Just as "phenomena" is the plural of "phenomenon", "criteria" is the plural of "criterion". Requires a plural verb: "the criteria ARE..." not "the criteria is...".
The selection committee will use several criteria to evaluate the candidates.
The criteria for admission to the program are listed on the university website.
All three criteria must be met before the application can move to the next stage.
Common mistake
Classic errors: "The criteria is..." (should be "are"). "One criteria..." (should be "one criterion"). "The criteria for this position is experience" (double error: criteria needs a plural verb). In formal writing, these errors are very noticeable. The same pattern: datum/data, phenomenon/phenomena, curriculum/curricula, medium/media.
Trick to remember it
Memorize the pair: criterion (singular, ends in -on) / criteria (plural, ends in -a). The same pattern as: phenomenon / phenomena, datum / data, curriculum / curricula. When you see "criteria", the verb must always be plural: "criteria ARE", "criteria HAVE", "criteria INCLUDE". If you see a singular verb, it is a sign the speaker confused singular for plural.
Quick rule
Criterion = singular (one standard). Criteria = plural (two or more standards). Criteria + plural verb always.
Did you know?
English words ending in "-on" with plural in "-a" come from Greek: criterion/criteria, phenomenon/phenomena, automaton/automata. Words ending in "-um" with plural in "-a" come from Latin: datum/data, medium/media, curriculum/curricula, memorandum/memoranda. In modern English, many of these forms are being replaced by anglicized plurals ("-s"), but in formal writing the classical forms are still expected.
Exercise 1 · Pick the right one
There is only one _____ for receiving the scholarship: academic excellence.
Exercise 2 · Pick the right one
The _____ for this award are long-term commitment, community impact, and innovation.
Exercise 3 · Form the word
Criterion = singular (one standard). Criteria = plural (two or more standards). Criteria + plural verb always.
Classic errors: "The criteria is..." (should be "are"). "One criteria..." (should be "one criterion"). "The criteria for this position is experience" (double error: criteria needs a plural verb). In formal writing, these errors are very noticeable. The same pattern: datum/data, phenomenon/phenomena, curriculum/curricula, medium/media.
Memorize the pair: criterion (singular, ends in -on) / criteria (plural, ends in -a). The same pattern as: phenomenon / phenomena, datum / data, curriculum / curricula. When you see "criteria", the verb must always be plural: "criteria ARE", "criteria HAVE", "criteria INCLUDE". If you see a singular verb, it is a sign the speaker confused singular for plural.
Bryan López
Founder of SpeakUP Academy