Use the correct word.

"Criterium" is a form of bicycle race. What is wanted here is the
singular of "criteria" which has Greek roots. The correct singular is
"criterion".

doc/Type/Hash.rakudoc

@@ -70,7 +70,7 @@ say { 'a',:b(3), 'c' }.^name;           # OUTPUT: «Block␤»
 
 The next-to-last two cases are examples of the generation of C<Block>s in the
 presence of the topic variable C<$_>. The last case does not meet the third
-criterium for generating a hash, and thus generates a C<Block>.
+criterion for generating a hash, and thus generates a C<Block>.
 
 A % in front of parentheses or square brackets will generate a Hash as long as
 the elements can be paired.