Comment by glaforge

No, Groovy is used in many other places than Grails. One can think of the Gradle build automation tool (http://gradle.org/), for instance, which uses Groovy as a DSL. But actually, one of the very big use cases for Groovy outside of Grails is as an embedded DSL, for business-oriented languages, to further customize the business rules of an application, for configuring it, etc. Groovy's used in many sectors: healthcare, insurance, banking, travel, scientific simulations, biomedical, etc.