The purpose of the thesis is to establish a model of meaning based on the logical analysis of empirical descriptions and explanatory definitions of a number of studies in architecture and psychology (e.g., the experimental work of Maslow, Gibson, Barker and Bronfenbrenner). The thesis provides an explanatory based method for better understanding architects' normative theories of meaning and suggests a new interpretation of the relationship between form and function in architectural and urban design theory and practice. It argues that meaning in architecture is a much broader topic that most current linguistic models assume. Linguistic models of architectural meaning are unable to address the complexity of the relationship between people and the environment. Although this thesis rejects traditional linguistic models, it does, however, use their positive aspects to establish a new association between form and its functions. It is argued that an understanding of the acquisition of architectural meanings can be achieved through a number of coexisting theories that are ecologically and psychologically oriented. Many theories, however, use a limited model of perception in their arguments. This thesis suggests that the information-based perception theory be the basis for the integration of these theories into an ecological framework. This theory is rich with reference to everyday life. An ecological model of architectural meaning is presented in this thesis. To rectify the problems of existing models of meaning and to be responsive to people's behaviour in ecological places, there are three main concerns. They are: 1) the definition of the concept of function in architecture and urban design, 2) people and their motivations, and 3) the people-environment relationship. It is argued that people's perceived meanings are the outcome of a cognitive interaction between human motivations and needs and the affordances of the built environment. The concept of motivation and the concept of affordance are given a broader definition here than in those existing architectural theories of meaning which have already used them. A model of human needs is presented. It is argued that built forms act as symbols of people's needs and therefore human aspects of architectural and urban designs are associated with the affordances of ecological places.