| Activin | Signalling molecule released during embryo development |
| Age-class modelling | modelling Modelling a population in terms of the number of individuals in different age-classes |
| Alarm | Simile component that allows the functions in a submodel to be evaluated multiple times, in order to perform an iterative calculation |
| Area (modelling changes in) | Modelling the changes land area, typically the area occupied by a certain land-use |
| Association submodel | Uses the Simile “association submodel” to specify a relationship between objects (e.g. ownership of fields by farmers) |