| Webster's Online Dictionary |
| Expressions | Domain | Definition | |
| Hardiness zones | Agriculture | See plant hardiness zones. (references) | |
| Plant hardiness zones | Agriculture | The USDA has divided North America into 11 hardiness zones based on average annual minimum temperatures. Horticulturalists and nurseries rate plants by their hardiness; the hardiness zone maps can then be used to determine the likely survivability of particular plant species and varieties according to one's local growing area. (references) | |
Source: compiled by the editor from various references; see credits. | Top | ||
