ABSTRACT This paper proposes a unified knowledge model establishing a core structure of knowledge representation in natural and artificial intelligence systems. The Concept Cell Model proposes the use of acyclic lattices to model a concept formed from a knowledge network of simpler concepts. Declarative and procedural knowledge are explicitly defined as the time-invariant and time-variant relationship of concepts. Examples of a Restaurant Servicing Concept Cell and an extended Shopping Complex Concept Cell are used to demonstrate the functionality of this model. Major existing theoretic and engineering Ontology knowledge schools are compared under this framework.