outgroup
a more distantly related group of organisms that serves as a reference group when determining the evolutionary relationships of the ingroup, the set of organisms under study
en-GB/aʊtɡɹuːp/
en-US/ˈaʊtˌɡɹup/
a more distantly related group of organisms that serves as a reference group when determining the evolutionary relationships of the ingroup, the set of organisms under study