classification clas·si·fi·ca·tion (klās'ə-fĭ-kā'shən)
A systematic arrangement into classes or groups.
The systematic grouping of organisms into categories on the basis of evolutionary or structural relationships between them; taxonomy.
The systematic grouping of organisms according to the structural or evolutionary relationships among them. Organisms are normally classified by observed similarities in their body and cell structure or by evolutionary relationships based on the analysis of sequences of their DNA. See more at cladistics, Linnean. See Table at taxonomy.