[vorg]

The comment you replied to actually said "Groovy and Grails" which is correct because Groovy was originally intended by its creator to be a standalone product with applications using it to be separate products, as with other languages. The phrase "Groovy on Grails" was promoted afterwards by some Grails developers who wanted their product's name to sound like "Ruby on Rails", regarding Grails as the only viable use case for Groovy of any adoption potential.