- 1. A biologic division between the genus and a variety or the individual; a group of organisms that generally bear a close resemblance to one another in the more essential features of their organization, and breed effectively producing fertile progeny. 2. A class of pharmaceutical preparations consisting of a mixture of dried plants, not pulverized, but in sufficiently fine division to be conveniently used in the making of extemporaneous decoctions or infusions, as a tea. [L. appearance, form, kind, fr. specio, to look at]- type s. the name of the single s. or of one of the s. of a genus or subgenus when the name of the genus or subgenus was originally validly published.
* * *1 a) a category of biological classification ranking immediately below the genus or subgenus, comprising related organisms or populations potentially capable of interbreeding, and being designated by a binomial that consists of the name of the genus followed by a Latin or latinized uncapitalized noun or adjective agreeing grammatically with the genus nameb) an individual or kind belonging to a biological species2) a particular kind of atomic nucleus, atom, molecule, or ion <production of DNA damage by active oxygen \species>
* * *n.the smallest unit used in the classification of living organisms. Members of the same species are able to interbreed and produce fertile offspring. Similar species are grouped together within one genu.
* * *spe·cies (speґshēz) (speґsēz) [L.] 1. a taxonomic category subordinate to a genus (or subgenus), and superior to a subspecies or variety, composed of individuals possessing common characters distinguishing them from other categories of individuals of the same taxonomic level. In taxonomic nomenclature, species are designated by the genus name followed by a Latin or latinized adjective or noun. 2. a group of objects having common attributes.
Medical dictionary. 2011.