Do you get confused when the plural of a word doesn’t end in “s”?
“Criteria” is plural (like “phenomena”), while “criterion” is singular, like “phenomenon.” You have one criterion or many criteria. It’s easy to be confused, since some words (e.g., “data” and “media”) are the same whether singular or plural.
Examples: Elsbeth Oggert detailed the six basic criteria for accepting a client…The restaurant has one criterion for entry: every customer must wear shoes or sandals.
Criteria: plural
Criterion: single