This paper reports the findings of an investigation into the development of the use and understanding of locative and temporal prepositions in 94 children aged from 18 months to 8 years. The research was carried out as part of the Project "Language Development in Pre-School Children," directed by Gordon Wells, at the University of Bristol, School of Education. The research represents an attempt to integrate the theoretical and methodological orientations of linguistic semantics and Piagetian theory in the study of the acquisition of a limited domain of word-meanings. Detailed analyses are presented of particular strategies utilized by children at various ages and stages of development in the comprehension and production of spatial and temporal relational terms. It is suggested that such strategies result from specific interactions between the developing systems of language, cognition and perception, the overall forms of which are determined by the socio-cultural context of the use of the relational terms. In conclusion, partial critiques are presented of one-sided applications of semantic features theories and Piagetian theory in previous explanations of the acquisition of spatial and temporal relational terms. (Author)