Genus–differentia definition

Genus-differentia definition is a way of organizing animals and plants into groups. It divides animals and plants into "genera" and then further into "differentia". Genera are the big groups and differentia are the smaller groups. For example, a Robbin is part of the Genus Turdus and part of the differentia migratorius. That means that Robins belong to the group of Turdus, which is a group of birds, and the differentia migratorious, which are birds that migrate each year.