Dispersal is a central concept in movement ecology. Here, we discuss this concept in the context of its historical and current uses in different research traditions. We further address the potential and need for general quantitative descriptions (models) of dispersal patterns and processes. As a framework for this discussion, we present a general conceptual movement process model capturing important phases of movements in all organisms: preconditioning, initiation, relocation, cessation and impact. In the light of this model, we discuss the relationships between dispersal and similar concepts like movement and migration, with particular reference to spatiotemporal and biological scale. We review general patterns and mechanisms of dispersal across organisms, and suggest sources of inspiration for further development and integration in this field. We highlight the importance of understanding dispersal mechanisms, using examples from biological theory and applications in pest control and conservation.