liik

Liik is a word in Estonian meaning "species" or "kind." In biology, liik denotes the basic unit of taxonomic classification, typically defined as a group of individuals that share a distinct set of traits and, in many concepts, can interbreed to produce fertile offspring and are reproductively isolated from other such groups. Because different species concepts exist—such as biological, genetic, or evolutionary—the exact criteria for delimiting a liik can vary among scientists and over time.

In scientific and educational contexts, the term is used to refer to the species level when describing organisms, often alongside the genus in formal nomenclature. Estonian biodiversity surveys, museum records, and field guides routinely employ liik to indicate the specific species identity of specimens or observations.

Outside strict biological usage, liik can also function in ordinary language to mean a kind or type of something more generally, not limited to biology. The term thus covers both technical and everyday senses related to categorization and diversity.

See also: taxonomy, species concept, biodiversity, nomenclature.