1. Biology a. A fundamental category of taxonomic classification, ranking below a genus or subgenus and consisting of related organisms capable of interbreeding. See table at taxonomy. b. An organism belonging to such a category, represented in binomial nomenclature by an uncapitalized Latin adjective or noun following a capitalized genus name, as in Ananas comosus, the pineapple, and Equus caballus, the horse. 2. Logic A class of individuals or objects grouped by virtue of their common attributes and assigned a common name; a division subordinate to a genus. 3a. A kind, variety, or type: “No species of performing artist is as self-critical as a dancer” (Susan Sontag).
b. The human race; humankind. 4. Roman Catholic Church a. The outward appearance or form of the Eucharistic elements that is retained after their consecration. b. Either of the consecrated elements of the Eucharist. 5. Obsolete a. An outward form or appearance. b. Specie.