rails/rails — pull request #11876 by sgrif (2013-08-13 22:44:41+00:00)
Title: Correctly singularize "criteria"

"criteria".singularize # => "criterium"
"criterion".pluralize # => "criterions"

A criterium is a bike race, the singular of criteria is criterion. I'm fairly sure this is an irregular, and not a standard inflection rule that needs to be added.