- A concept that cannot be defined in terms of other concepts.
- 1936, Arnold Dresden, An Invitation to Mathematics:
- Every concept admitted in geometry is either a primitive concept, or else is obtained by a definition in terms of the primitive concepts.
- 2005, Rolf Engelbrecht, A. Geissbuhler, C. Lovis, Connecting Medical Informatics and Bio-Informatics:
- A primitive concept is essential to the representation of the specialty. A defined concept is built from one or more primitive concepts and one or more relationships.