(1) The science of finding, describing, classifying, and naming organisms, including the studying of the relationships between taxa and the principles underlying such a classification.
(2) The classification of organisms in a hierarchical system or in taxonomic ranks (e.g. domain, kingdom, phylum or division, class, genus, species) based on shared characteristics or on phylogenetic relationships inferred from the fossil record or established by genetic analysis.
For example, organisms are classified into clades (i.e. a taxonomic group of organisms based on homologous features derived from a common ancestor) in phylogenetic taxonomy
Word origin: from Greek taxis, arrangement, order + -nomia, method, from -nomos, law, managing, from nemein, manage.
Related forms: taxonomical (adjective), taxonomically (adverb), taxonomer (noun).
Related terms: chemical taxonomy, numerical taxonomy.