Cladistic

Part of speech: adjective

Definitions

1. A method for organizing living organisms based on their evolutionary relationships as determined by shared derived traits
2. A classification system that sorts species into groups reflecting their evolutionary history through common characteristics
3. A scientific approach to categorizing organisms based on their evolution as indicated by shared traits and lineage relationships

Etymology: "Cladistic" is built from "clade," a term taken from the Greek "klados," meaning "branch," which is what a biologist sees when tracing a family tree of species. The noun "cladistics" was formed from "clade" with the suffix "-istics," and "cladistic" was then back-formed from it, so the adjective came after the noun it seems to derive from. The suffix itself has a long pedigree: the Greek "-istēs" denoted someone practicing or following something, and it passed through Latin "-ista" and Old French "-iste" into Middle English before settling into the modern "-ist" that also produces words like "botanist." The "-ic" ending traces a separate route. The Greek "-ikos" became Latin "-icus," which reached English through Old French "-ique" and Middle English "-ik," and later "-ic," so that "cladistic" combines a branch-based noun, a practitioner-style suffix, and an adjective ending, each arriving by a different path.