OOP is based, partly, around the idea of 'mini algebras' (roughly speaking, public interfaces), which are domain-specific languages ( http://xahlee.info/comp/Alan_Kay_on_object_oriented_programi... )
Functional programming, especially Haskell, tends to use the term 'embedded domain-specific language' ( http://wiki.c2.com/?EmbeddedDomainSpecificLanguage )
Lisps tend to call them DSLs or sometimes "mini languages"
Forth calls them "vocabularies"