Earth’s land cover consists of forests, agricultural land, urban settlements and a large, heterogeneous category that includes deserts, grasslands, savannas, shrublands and tundra. This heterogeneous category has eluded a collective designation comparable to that of forests, which has contributed to its omission from multilateral programs and critical global initiatives. Potential designations for this land category – drylands, grasslands, grassy biomes, open ecosystems and rangelands – were evaluated for their relative advantages and disadvantages. Grassy biome is recommended as the most appropriate designation because it conveys a meaning that is distinct from forests, emphasizes that grasses often coexist with other plant growth forms and has great utility for use by multilateral organizations. However, the criteria of tree canopy cover >10% used by the Food and Agriculture Organization (FAO) to define forests represents a major obstacle to implementation of the grassy biome designation. This minimal canopy cover infringes on global savannas that occupy 20–25% of global land area. An assessment of the functional plant traits determining the shade and fire tolerance of savanna and forest trees indicates that a minimal tree canopy cover of 45% represents an ecologically appropriate demarcation between savannas and forests.