| Basic System Dynamics | Denotes a System Dynamics model containing only compartments, flows and variables |
| Biomass | The amount of biological material |
| Branching | As in tree branching patterns, root branching, etc |
| Broom grass | A type of grass grown in parts of Africa, for thatching etc |
| Budworm | Insect pest in Canada |
| Business model | A model of some business process, e.g. cash flow, sales |