Some sources use the term "language isolate" to indicate a branch of a larger family with only one surviving member. For instance, Albanian, Armenian and Greek are commonly called Indo-European isolates. While part of the Indo-European family, they do not belong to any established branch (such as the Romance, Indo-Iranian, Celtic, Slavic or Germanic branches), but instead form independent branches. Similarly, within the Romance languages, Sardinian is a relative isolate. However, without a qualifier, "isolate" is understood to mean having no demonstrable genetic relationship to any other language.