- The study of classification systems and nomenclature.
- 2009, Victor Lux Tonn, Systematics and the Economics of Culture, →ISBN, page 187:
- Systematics is intended to be the study of "qualitative" and structural aspects of all things in the universe; and if feasible, is designed to absorb eventually the "quantitative approach" of mathematics toward human and physical worlds as well. It is hoped that systematics will be able to develop a quantitative field and thus to enable it to incorporate mathematics into its realm of studies some time in the future.
- 2012, Ward C. Wheeler, Systematics: A Course of Lectures, →ISBN, page 2-6:
- Trees are the central objects of systematic analysis. Taxa are ordered, characters explained, and hypotheses tested on trees. Since systematics informs and draws on other areas of science, there is a diversity of terminology for trees and their components.
- The systematic classification of a branch of science, especially the classification of organisms.
- A branch of Christian theology that formulates an orderly, rational, and coherent account of Christian beliefs. It comprises dogmatics, ethics and philosophy of religion.
- 1990, Robert M. Doran, Theology and the Dialectics of History, →ISBN, page 7:
- Systematics is an effort to understand those specifically theological affirmations that the theologian holds to be true and so regards as doctrines.
- 1990, Bernard J. F. Lonergan, Method in Theology - Volume 12, →ISBN, page 335:
- The seventh functional specialty, systematics, is concerned with promoting an understanding of the realitites affirmed in the previous specialty, doctrines.
- 2006, M. James Sawyer, The Survivor's Guide to Theology, →ISBN, page 208:
- Not exegesis itself, then, but biblical theology, provides the material for systematics .... Bliblical theology is not, then, a rival of systematics; it is not even a parallel product of the same body of facts, provided by exegesis; it is the basis and source of systematics.
Depending on context, when used to mean the classification of biological organisms, this may be the same as taxonomy or distinct. When distinct, systematics can mean the research into the relationships of organisms (phylogenetics), while taxonomy involves itself in the recognition and the naming of taxa. Alternatively, Systematics can mean the broader category that includes both phylogenetics and taxonomy.